I just read, that non magical armor parts like boots, helmets and bracers have no effect on an my AC.

So what`s the point of wearing them?

For fashion reasons only.
You'll find a helmet +1 and boots +1 in EoB 2 but due to rings of protection +1/+2/+3 those would be completely useless and in EoB 3 game they are going to be converted into common items anyway.

Bracers on the other hand are very useful, especially for your weak mages in the back. I strongly suggest to choose Bracers of Defense in one particular room.

Helmets are especially weird. One would think slapping some leather and/or metal onto your cranium would at least provide some minor protection for this incredibly delicate area.

Of the older DnD games, I think Baldur's Gate's helmets provided protection against critical hits at least.