This is the answer I was looking for but sadly, this type of insignificance becomes ammunition for managers/founders who are obsessed with novelty

This is almost always the case, no matter the service we're talking about.

Is this how we ended up with electron for desktop applications and Java for backend?

Yes, because developers and expensive and so developer productivity dominates almost everything else.

Also, "pick what you know" applies here, too. If you know NGINX, then all you get from switching to Caddy is experience, and likewise, vice versa.

*and memory safety*

This cannot be understated. Caddy is not written in C! And it can even run your NGINX configs. :) https://github.com/caddyserver/nginx-adapter

A solution in search of a problem.

Nginx security page [0] lists a non-zero amount of exploitable issues rooted in manual memory management.

[0] https://nginx.org/en/security_advisories.html

When would it matter? I write in Python, so performance was never a concern for me, but I am curious the scenarios in which this was likely to be the weakest link in real workloads.

Given available options, I will take the network software written in a memory safe language every time.