Nginx is annoyingly complicated in a microservices environment.

IP addresses of upstream servers change, and sometimes DNS doesn't resolve until another service is brought up. Nginx does not work well in such an environment unless you (1) have ugly configuration hacks, (2) add OpenResty/LUA to your configuration, (3) add a watchdog process, or (4) buy their nginx Plus version and keep track of how many instances of nginx you have.

I want simple. If you need a webserver that can use DNS, Nginx is a lot of extra work.