I self-host my own email, have done so for years. I’ve not gotten pwned. Use an SSH key and a firewall, only expose the ports that should be public, have reasonable access controls, etc, just practise general cybersecurity—it applies to servers too.

I know everyone complains about hosting email. But I’ve not run into major problems. My emails get through spam filters and I have good uptime. It’s also a fun learning experience.

If the authors used the same method to improve GIMP, they’d be introducing a bunch of slop code to GIMP. This code is not going to be of GIMP quality.

I also doubt this will hold a candle to GIMP for the aforementioned reasons. It might appeal to a small audience, but I do not expect it to dethrone GIMP any time soon.