That's kind of my point. Even you eschew Paint's simplicity when you need a more complex transformation. Nothing you do in Paint.Net isn't impossible in Paint, given enough calculation and preparation. So a performance isn't the deciding factor. It's the speed of achieving thing X (of which startup/lag is a tiny cost).
Similarly in Paint.Net you could emulate many Photoshop features (e.g., non-destructive editing), but doing so would be tedious (duplicate layer, hide layer adjust copy layer, then edit until you get it to where you want it).
Performance is a deciding factor, it's the reason I use paint and don't use Krita/Gimp/Photoshop. I use Ctrl+Z for non-destructive editing in paint. Also paint has a more reliable and predictable UI, you never know what those overly smart editors will do. Will they add too much antialiasing? Randomly switch to subpixel precision? Insert transparent background (antialiased)?
There are two things in play: just because it's a deciding factor for you doesn't mean it's a deciding factor for everyone else. Second, even for you, Paint isn't enough. You also got Paint.net. You can reproduce almost any effect in PS or Gimp or Krita in Paint/Imagemagick. Why not just use those two for everything.
It's the same thing as using an IDE vs notepad(++). Anything done in the IDE behemoth can be done in notepad. Albeit at a significant time penalty, and with way more CLI jousting.
> I use Ctrl+Z for non-destructive editing in paint
That's not really non-destructive editing - that's Undo. A non-destructive editing means you can edit, change things, save, close the program. Reopen file after X days amount of time, and change effect or thing you applied.
That's kind of my point. Even you eschew Paint's simplicity when you need a more complex transformation. Nothing you do in Paint.Net isn't impossible in Paint, given enough calculation and preparation. So a performance isn't the deciding factor. It's the speed of achieving thing X (of which startup/lag is a tiny cost).
Similarly in Paint.Net you could emulate many Photoshop features (e.g., non-destructive editing), but doing so would be tedious (duplicate layer, hide layer adjust copy layer, then edit until you get it to where you want it).