Oh yes, the PIO is very cool and somewhat unique. The list of examples of things that can be implemented with such a tiny "computer" (9 instructions assembly language, program size maximum of 32 instructions) is quite impressive:
In fact, the rp2040 examples and SDK docs are very, very good compared to most traditional manufacturer's documentation and by itself makes it a very good value proposition for hobbyists.
https://github.com/raspberrypi/pico-examples/tree/master/pio
In fact, the rp2040 examples and SDK docs are very, very good compared to most traditional manufacturer's documentation and by itself makes it a very good value proposition for hobbyists.