Before the men's coat came in many forms, men used to cover themselves with simple sheets of more or less thick fabrics. The Greeks spoke of chlamydia, and the Romans of togas.
Later on, the Romans adorned themselves with a cape: a garment that will live through the ages. It is only in the XVth century that the cloak becomes more democratic and gets closer to those we know today.
The coat represents a carapace and plays an important role in your image. Of course it protects you from bad weather, but also, unconsciously, from the outside world.
It is not uncommon to find very fine coats, which are no longer really used for protection, but which offer presence.
But whatever your choice, avoid synthetic fibers that do not breathe (except for technical fibers really intended for this purpose).
Prefer natural fibers such as fur, wool, mohair, cashmere (or camel, yes, it's serious). You are going to wear your coat for a long time, so don't neglect this purchase.