There isn't one build just for hex, you can go for any build that works for your gear and skill.

When summerholt expansion came out the mobs were way op, so people started trying str/int builds to compensate, that seems to be when most went to str builds (often 50/50). It's not that the staff will be better due to your build but it will shine against certain mobs (like giant skeletons), or in certain maps like higher level maus maps.
The staff is popular because it works well against mobs with high hit points, it reacts to some pets aa really well (like magma), and complements any damage over time effects, which the Mage has a lot of (fire, clock, ice).

It's fun to use in gy just for the hell of it, but honestly a dusk staff works just as well if not better because the mobs don't have high hp. I only break mine out in maus 4+, otherwise it's just for jewel farming.

Personally I'm no fan of str build smurfs, I'd rather them stop being wimps who slow down my runs XD