I have a Raspberry Pi 4. I bought it because I wanted something to tinker with, but I have not thought of anything to tinker about. I do have it set up to access my NAS unit so I can use it with LibreOffice. I bought a small touch screen for it, but I haven't done anything practical or fun with that.
I keep thinking "robots." Nothing fancy.
That always gets me interested.
My oldest son has two Raspberry Pi. One is a Raspberry Pi Zero. He designed an interface to control a watering system he designed for some trees in pots. I was very impressed. Every morning at 8:00, it goes off for one minute, and the shuts off. It stops the water immediately and ALWAY makes loud BANG in the pipes.
I don't recall what he did with second one. I know he has a camera hooked to it.
Like babybird said, The pi is very quiet. I love that.