Because if the AI is in paint it gains the potential to monitor everything you do in paint. Deliberately or acidentally click the AI button? It now gets to steal your work.

Notepad had a "Copilot" button at one point. No clue if it's still there though since I'm fully on Linux now.

Because AI is your shiny new hammer and everything is a nail now, so you really, really need to use it...

On a more serious note: Cramming AI into everything (and even inventing new stuff that absolutely needs AI for some reason) and then making people heavily pay for AI once they can't escape that bullshit anymore is basically the only way to ever get the insane investments pumped into the AI bubble back. And even that is highly questionable.

Putting AI into software that doesn't need it isn't even registering on the insanity scale anymore given that there is now 'AI included' advertising on fucking tooth brushes.