They have great software support and Google-ability, which also means LLMs understand how to work them. I use them in scenarios where I want both Linux and GPIO. Specifically, right now I have 4 Pi 5s running kiosk displays with RGB LEDs around the outside of each. The displays show a web page, requiring something powerful enough for modern Firefox, and the LEDs are synchronized to the state of the web pages. You could do this with a mini PC and a microcontroller, but it’s just way easier, and cheaper, to use a Pi.