The only downside is you can‘t use apps/plugins which require additional local tools (e.g. ocrmypdf) but others can be used just fine.
Calling remotely hosted services works (e.g. if you have elasticsearch on an vps and setup the Nextcloud fulltext search app accordingly)
The sad part is that their cloud services also often don‘t support basic features which their self hosted software offer…
But either one can only work with s3. His library works with many other backends. Get it? I'm saying he should consider integrating with goofys!