I like that "probably" for perfomant here, but let's focus on features so far.
Let's imagine we go this way, implemented own self made webserver in nodejs, started using it and the next day it will be required to add simple things like basic auth for specific location or ACL based on Maxmind geo data or even setting straightforward round-robin balancing among several php-fpm upstream, even without weights - what would be the flow here? Involving dev team and trying to put those tasks into their backlog?
Why it's better than just adjust Nginx config in 5-10 minutes?