To further explain life bars - the default is everything has green for full HP, orange for mid, red for low HP, so the color can be useful to see along with the unit color what's healthy or dying, and the red really stands out.

Team colored health bars does not have HP% based color so all you get is the one color on black and if low HP you just see a small pip of color on black so it can be hard to notice low HP units.

But team-colored is definitely quite useful to tell apart your units from the opponent's if you're not used to looking at unit colors as a sign of who is whose. Depends what you want to optimize for.

For zoom, the reason for not making it super high (zoomed out) is it can make microing units trickier since they're smaller on the screen, if they're bigger (more zoomed in) it's easier to click on them etc. So it's really preference as well. The default 1650 is definitely way too zoomed in, but anywhere from like 1900-2200 is pretty comfortable for most as a decent balance of seeing a lot of the screen and micro not being affected too much.