I understand that modern outer layers are more functional. A leather jacket, for example, can be dressed up or down so as to be worn in a variety of situations. It is also better at keeping you warm.
However, I think capes/cloaks are more aesthetically pleasing garments. It also feels good to have the fabric flowing around you as you walk. But what do you think?
The “British Warm” was the intermediary as I understand it: a shorter greatcoat favoured by Britsh officers in WW1. The Trenchcoat itself was modeled to fit over, accompany or replace this.