This. I have been running it the same way for some time now. Even if you change something on one machine and something else on another nextcloud will just happily inform you of the conflict and then you can open both databases and cherry pick. Never had corruption issues.
Worked as a sysadmin for years dealing with all kinds of certificates. Liek others have said if you can’t automate the process a paid certificate buys you 12 months at a time in validity. Also wildcard certificates are more difficult to do automated with let’s encrypt. If you want EV certificates (where the cert company actually calls you up and verifies you’re the company you claim to be) you also need to go the paid route
In my experience trustworthyness of certs is not an issue with LE. I sometimes check websites certs and of I see they’re LE I’m more like “Good for them”
I think a large factor is because so many people use it. A lot of people come to self hosting without much knowledge and just copy configs etc. from a Tutorial. Those tutorials will 90% of the time use Apache or nginx. I remember back when I set up my first servers I mostly followed instructions and copied configs. Years later I understood I had set up Apache with virtual hosts and what that means/how it works but it might as well just have been nginx.
As for why so many people use these two I think it also has to do with “adoption” in another way. Back before nginx Apache was the standard everything else was “different”. Then nginx appeared to solve the Problems of Apache and then there were 2 … These days you can probably do anything you want/need with the 2 servers so no reason to use anything else.
Professionaly I usually use either HAProxy and Apache or Nginx (or sometimes HAProxy and Nginx) but if there are special requirements that might change.
Nextcloud.
I was hosting nextcloud at home for years. Then when I worked in a Datacenter I got to host some servers there from free so I set up a two-node proxmox with nextcloud and some other stuff. Now I don’t work there anymore and I really felt the hole nextcloud left, no more notes syncing for notes, tasks, calendar, podcasts no more place to upload my photos from my phone … So now I’m hosting nextcloud at home again.
I also host jellyfin which is nice but if I don’t have it doesn’t actively hamper my workflow.