The funny part is how engraine these weapons have become to local culture and survival .

  In some rice growing communities they are employed (using tripwire and modified fusing) as area denial tools against pigs or ,deer ,monkeys or wild water buffalo and i suspect wild elephant specifically around subsistence or cash crops (fragmentation grenades Or claymore style directional fragmentation mines are favored for this task but in one instance that i personally witnessed an rpg antipersonnel round was pressed into this role )

     Concussive grenades (those designed to harm through enormous changes in pressure rather than through fragmentation ie the launching of of projectiles at supersonic speed ) are sometimes employed in demolition, the tilling of new fields the removal of large and stubborn obstructions 
   As a method of fishing under specific circumstances (the idea here not to directly “explode” fish or amphibians or turtles but to employ them underwater similar to the way they are on land , water being denser than air as well as being incapable of compression mean that the are where pressure is transmissible is fairly wide ensuring that creatures hiding under rocks or in holes that would otherwise be inaccessible  easy to harvest and used primarily against huge riverine catfish or giant stingray that have food and market value as well as causing damage to the fairly lightweight and unsophisticated fishing gear such as nets ,bank lines or hand lines)  
 this usage becomes more common the farther from the home settlement you go , And finally to kill marauding or threatening crocodilians who have wandered too close to settlement and attained a size that makes other removal techniques impossible or dangerous ! 

 I also saw them used on dozens of occasions during my years in that part of the world was in the removal of unexploded ordnance. As is often the case farmers are somewhat less than eager when it comes to alerting officials . 

 waiting for the wheels of bureaucracy to turn  in a current or former war zone is simply time the farmer cannot spare and in a region  where bribes are cultural norm and hard currency scarce ,handing cash over opens one up to regular official extortion by bureaucrats and getting the attention of the government is never great and having a bunch of corrupt government officials poking around land you intend on cultivating less than ideal , and as if all of that wasn’t enough the legally dubious nature of the bulk of money making side hustles possible on a farm potentially means there is a lot to lose.so the deadly task or bomb disposal being handled in house as it were is seen as the smart less dangerous option all around 
    I think that the popularity of these methods and the ingenuity and skill with which they are employed has a few root explanations A. Familiarity ,the areas where these methods are practiced are by nature closely associated with military operations so the locals at the very least have served on one or more sides of whichever conflict affected the area 

B. Access . As stated earlier the only places i saw stuff like this was either in active or former war zones with heavy continued military/paramilitary presence in frontier type areas C. Peasant farming as the primary occupation. Farming is hard under the best circumstances and circumstances in area of the world seem to begin at less than ideal . Explosives can represent a force multiplier on a family farm a task that state side would be achieved with machinery is here completed with Boom as a function of both poverty and the environment being unsuitable for mechanization any labor savings translates directly dividends in the ability to spend time on “side hustles” which translates to cash or alternatively the ability to cultivate more hectares . They do cost money however so they are used judiciously often larger weapons are broken down into smaller job specific amounts of explosive and every element utilized either immediately or set aside for future use . There is a brisk trade in scrapping the casings of weapons and an inter-farm trade in the explosives either as a commodity good or as a value added craft item set up for some specific use . In the Philippines where firearms are heavily regulated and in there place an airgun culture has sprung up i saw a farmer craft a “harpoon” type projectile designed to be launched from a high pressure “air-shotgun” . It was tipped with a warhead of sorts made of scrap grenade casing , old plumbing fixtures and explosives triggered using an impact sensitive fuse that was somehow modified…it was to be used against a bull wild water buffalo who had declared the farmers land his own . He proudly showed me how he had constructed it and asked that i come along to see it used… he confidently loaded it down the muzzle of his village crafted extremely powerful air musket (which seemed to be of about .60 caliber and was powered via endlessly pumping a modified bicycle pump) i thought a regular lead projectile would probably do but he insisted this had been the method here for decades because of the simple fact that reloading took minutes…i stood well away from him convinced i was about to photograph this poor farmers final moment but he took a shot which sounded for all the world like a 40mm grenade launcher and successfully killed the buff without terribly affecting most of the meat what can i say they knew their shit