I use ISO 400 film most of the time. Sure, it can't handle extreme situations like you mentioned but it does handle most situations very well. To me, it's very convenient. If I was going somewhere on bright sunny day, like beach, pool, or somewhere and it's going to be like that all day long, I load ISO 100. If I'm going to be indoors and flashes aren't allowed or not going to be used, I usually push Tmax400 or Tri-X to 1600 or go straight to Delta 3200. Otherwise, I just load ISO 400.
I also don't load film until I get to the site, and I typically take 100 and 400 with me.
I experimented with Tri-X and Tmax400 pushed to 1600 and compared that against Delta 3200 at 1600. They were actually remarkably similar.
I'm not sure what camera you are using but mine can handle 1/4000. I also don't hesitate to stop down way more than f/8 - unless of course I need shallower DOF.
Various film speed exists for purpose. So why not take advantage if you are going to be in extreme situations?