I only wear suits when I have to, but I've worked in "suit environments" many years. Suits have many purposes, like hiding the truly horrible bodies that some have, Trump is an example. They also prevent people from showing up to work in garish or outlandish outfits which may be distracting or offensive to some. Also, they make dressing up to go to work really simple.

That said, I live in a place that has really hot summers, like 40C+, and wearing a suit in summer is really uncomfortable, even those linen summer suits. It'd be great if there were a number of accepted formal attires. For hot weather I like the caribbean "Guayabera"