Tank stance is a learning tool.
You use it to say "okay, i'm going to be hit for this amount, and I can afford to mitigate it this much." Even then that only applies to end-tier raids and such, EX primals and whatever like that. But just doing dungeons? Eh. The "aggro is a tank's job" meme is a bad one and needs to go away. Yoshi himself stated that DPS should learn to use their hate tools, like Diversion and such. If they aren't and stealing hate from you? That's their fault. They get upset? They're just not playing the game as it ought to be played: as a team endeavor.

In PF/DF where you can't guarantee that the DPS know how to play their class properly, any and all DPS helps things go smoother.

But. You should only be doing what you're comfortable with ultimately.