Ben Eater also had a video series about designing and making his own CPU from logic chips. He switched to 6502 likely because progressing up the stack, it started to become too big.
When I do a "microcontroller project" then I slap an ESP32, Arduino, or Pi Pico on the breadboard -- not a 6502.
Now, nothing prevents you from still using a 6502 based project for “real problems” as well, and it’s fun to use your pet project for something practical every once in a while, but that’s usually not the focus. The focus is learning, building, intentionally reinventing the wheel so to speak.
In my previous comment to you, I mentioned how Ben Eater made a self-designed CPU in his excellent video series, before switching to the 6502 to explore higher abstraction layers. In that case it may be more obvious that the focus was on designing the CPU itself, not on any a priori application use case for it.