“with an nice client?”

You gave the answer to yourself. There aren’t any user friendly multi-platform clients with synchronization / conflict resolution / versioning.

In my opinion, they do different things.

SFTP/SCP are great ways of transferring files between computers. I prefer rsync for most things because it can resume transfers and checksum results. I’d never use FTPS because SFTP/SCP comes with SSH, and why run a separate service? SSHFS is another way to use SSH to transfer files (it mounts a remote file system to your local computer so you can use all your normal file management tools).

NextCloud (and similar) do a bunch of additional things:

• Provides clients which sync files to your local computer
• Provides a web interface for managing files
• Provides ways to share files without creating accounts
• Allows connecting external storage (eg. S3)
• Provides encryption
• And a lot more

If SFTP does everything you need, that’s awesome. Use it. :-)

The reason for downvotes is comparing apple and oranges, and also throwing FTP in the mix!

Let’s consider SFTP and nextcloud. SFTP is a secure respected protocol for file transfer. If you use key authentication and disable the password authentication, it approaches to be bulletproof security wise. SSH has rarely had a vulnerability that would allow attackers in. It’s even have post quantum cryptography. It’s rather easy to set up. But it doesn’t do more than file transfer. It also doesn’t have a lot of GUI apps.

Nextcloud is like Dropbox. You can find A LOT of things in it (though frankly the quality of most of them may be low). File transfer is just one of the things that it does. It uses https, why? Because the web technologies and developers have focused on this versatile protocol in the past decades. You access internet through port 443 not 22!

If I want to backup data or transfer files, I use SFTP. Over the internet, I trust SFTP not nextcloud. For other things, I use other tools such as Synchting, nextcloud etc. Synchting allows syncing over SSH.