It’s not only the user experience, but clock timing internally as well as externally that is vital. If the device has a sloppy clock because of interrupts and a shared CPU with an operating system deciding resource allocation you are going to have a sloppy sequencer. Low latency and solid clocking (not just MIDI) is essential to audio/midi sequencers working well with themselves and each other
Just search around for people not being able to get their hardware to sync with Ableton Live (on a computer with a shared CPU) if you want to see examples. If Ableton can’t make it work reliably… well you get the idea
If you look at the majority of pro audio equipment, you’ll see that almost all of it is done on microcontroller or equivalent components(and for good reason). Much of it is written in Assembly or C to get as close to the machine language as possible.