They even work with phones!

The main difference is probably that many people had a C64 in their bedroom, so there's a lot of childhood nostalgia involved. Fewer people probably had a mainframe computer with punch cards in their bedroom. ;) Such emulation would probably be more interesting from a pure preservation perspective, and be less about nostalgia.

I prefer local. Do you know of a good macOS SID player? I'd love to drag out some of my old files.

Esp since there arent graphics routines in the c64 to speak of! There are no plot, screen clear, line, etc. Every program rolls its own.

As a joke a real freak could polyfill/hijack e.g $ffd2 output single char to cursor position in native pico code instead of 6502 to accel basic programs. That could be weird and phone to speed up all thise routines... but at that point just clock it all faster :)