Lovely thing about the BBC was the I/o breakout that meant you could easily wire it up to another processor and do stuff. For those of us at the time, growing up with alternative systems, such features were a real wonder, and a reason to lug everything over to my BBC-owning neighbours place for a weekend hacking ..
I love it that this ethos has persisted in the ZX Spectrum Next design[1], which also allows for the .. limited .. 8-bit (well, max'ed out actually) machine to access a .. rather large super-computer, by comparison, and by that I mean a raspberry-pi Zero ...
I wonder, if ZX Next is a paradigm which develops further into a viable market (imho, this already exists, elsewhere and otherwise..) then what sort of crazy machines might we be sporting on our wrists and in pockets, soon enough?
I mean, ZX Next ideology, in a PDA ..
[1] - https://www.specnext.com