I don't, mostly because I watched Asmongold talk about it, and now I feel weird playing with a female character online.

Though singleplayer I don't feel any problems: Lara Croft, Rynn, Chell, Rayne, Jade - it's all fine.

Maybe it's just for customizable characters?

I tend to play both, as I have set builds for set character names. First time playthrough in a soul's game? Maxwell is the name (though Maxwell is one of the few characters that I have played as both male and female.) Making a sniper build? Novikova is da girl for the job. A viking or warlord? Kaytlyn is my go to. Stealth? Garrett will get in and out.

I like having a roster to characters of any gender to pick from. Though, I admit, I tend to gravitate towards making femboy type characters lol.

It makes no difference to me.