Watching a Z80 from an RP2350

I think that 7 decades's worth of telly and movie set designers will take issue with the claimed uselessness of blinkenlichten. Blinkenlichten make money. (-:

Is it difficult to hook microcontrollers together?

My outside understanding was that you match the voltage ranges of the pins via a level shifter, and then match the sampling rate with a dedicated clock pin?

I guess what I'm asking is, this is cool, but what problem does it solve?