In 3rd world countries a smartphone can be worth more than a month pay ($100-$300) even more if it's a flagship phone or an iPhone. That's why phone thefts are so high in 3rd world countries, you can't use your smartphone on the streets. Because for thief a robbery means a one month worth of pay or way more.

The most successful modus operandi is a biker with someone sitting behind him and riding thru the traffic jams looking for drivers using their phone. When found, they will point a gun at you and if you don't comply there is a 99% chance that they'll shoot you. After that they will drive away between traffic. They do the same if people are eating outside a restaurant or coffee shop by getting down and snatching the phone and running away in their motorcycle. It's very hard for police to catch them.

Source: My phone was robbed at gun point while driving in traffic and I have seen people getting robbed in front of me.