I guess more digital art options on Linux are always good, but that aside, is there even a good reason to use it when something like Krita exists? It's always worked flawlessly on my linux machine (Mint).
It’s lighter, simpler, and faster with a much more intuitive UX. for basic image manipulation tasks it’s awesome.
For creation of art I’d use Krita, it is more feature complete. But if Paint.NET appeared on Linux, I’d use it in a heartbeat.
Paint.NET is closer to Gimp, but usable.