> If it's a basic operating system functionality (dealing with files, viewing photos) it's fine if you can't uninstall it, but then it better not come with any kind of separate user agreement, separate updates, changes in functionality, upselling attempts etc.

Which is the case for Google Photos. It is also a messenger (not kidding), shows notifications with "moments" it automatically created from your photos, lets you create photo books which you can order and so on.

I would prefer a smaller default gallery app with Google Photos being an optional extra.