If you remove the app-platform role from Nextcloud by separately hosting the individual apps, what benefit do you get from having both Nextcloud and File Browser?
Nothing really. For almost any Nextcloud feature out there, you can find a server app that does the same.
But that’s the point in my opinion. I don’t want to waste time managing tons of apps if I can manage one Nextcloud instance. Nextcloud basically decides for me what’s the best way to get those features running, so I don’t need to figure out myself.
Now if you’re into self hosting one container for each feature, go for it, no reason to not do so.