I don't understand why it's so difficult for people to understand.

If you're using the Pi as a microcontroller that you can run Python on, then just get the cheapest Pi that meets your needs.

If you're using the Pi for computationally expensive tasks then pay more money and get the fast one.

Personally I have a Pi 5 and it's perfect for me because I want small size but high performance. People say "just buy a real computer" but that would be higher energy and larger footprint.

The whole point of these things is that you use them for whatever you can imagine. Since different people have different imaginations it only makes sense that there's a range of different devices to suit everyone.