Who positions their speakers straight ahead (zero tow in) and why.

There are many reasons to fire straight forward, many have nothing to do with hot tweeters. 

All other factors being equal, I have found that every speaker requires different (if any) toe-in. I have also occasionally experienced the need to change positioning based on a change in electronics .

I have 3 setups of highly different calibur. My main system with Vandersteen Quattro Woods, a second system with Vandersteen IICe, and a 3rd with older pioneer HPM60s. All of them face straight forward. My experience is that you can dial in the center image to be pinpoint with toe in but you lose a ton in terms of soundstage width and depth. I've tried it all different ways with all the speakers. No toe in for me

I have 1.7is w/  about 20-25 degree toe-in, tweeters inside in a fairly large room and the soundstage is pretty wide for me.  I sit 9ft away and the sweet spot is  about 5ft across.  In my room, the soundstage varies from just the sweet spot to deep behind the speakers and a few feet wide of them ( speakers are 10ft apart), depending on the music.  I’ve experimented with less toe-in to straight on; both sound good but I  prefer the tighter sweetspot (no one else in the household  can stay still and just listen  enough  for me to widen it)…BUT, I will try the incremental method again to see far wide I go and still keep the amazing detail. 

I did for years until I learned about toe in.  I have one pair of towers with no toe in and they sound good in a large open room.  I toe in the other speakers I have in smaller rooms with more surface reductions.  Adjusting speaker placement as needed and preferred is a fun part of this hobby in my experience.