This I don't understand. DINsync is raw trigger outputs/inputs like you'd have in a modular synth, in contrast to MIDI that has to send serial messages over a 1k data bus.

Perhaps this take has something to do with calling a five-pin DIN plug '5-pole'? Something's wrong and backwards here.

Again, I guess this is where we are now? I remember reality, but here we are.

DIN sync is not trigger based, it's a full clock protocol invented by Roland that has various different states. The fact is that not all DIN sync capable machines implement it the correct way, leading to slight differences in synchronisation, even between devices made by Roland.

No, this is different from pure CV. Each device has its own (digital) sequencer that can synchronize with others using pulse trains over DIN cable. Lots of places where latency and instability can occur!

https://en.wikipedia.org/wiki/DIN_sync