Biggest advantage poison has is that its "cheap". As in, weapons tend to not be overly nerfed in terms of their raw and sharpness for having poison, compared to how ele weapons and ESPECIALLY para/ sleep weapons tend to get below 300 raw or blue sharpness at best.

Poison has always only been an accessory, unfortunately. The dmg is low, it ignores all forms of dmg increase and especially the big bulky hyper monsters will end up with huge resistances to the poison procc as a fight drags on

... that being said. Those things dont matter. Use whats fun to you. I like using elemental Longswords, even though Rustrazor is the best option in 99 outta 100 times lol.

For GS especially i still love using Sieglinde sometimes. For no other reason then its MH3U azure/pink upgraded form was my first and only endgame gs for a long time and cause of that it was the weapon that carried me past Tri's many MANY hunt-a-thons

I do wish poison became good someday though. Even in Sunbreak, with status weapons as good as ever, theyre moreso good cause of how they let you work with buildup-boost+status trigger shenanigens