I never understood why RJ-style connectors didn’t take off in the computer space outside of Ethernet and modems, which tend to be the most telecom-adjacent parts of the business. NIH syndrome? Thicc cable connectors convince people your $5k IBM AT isn’t a toy?
For low-voltage, low-speed stuff, it’s an obvious choice. I think pre-ADB Macs (128/512/Plus) used it for the keyboard, but there’s no reason we needed those awkward mini-DIN PS/2 and ADB cables that always involve fighting with orientation. Maybe even RJ-45 based serial ports.
Hell, why not design a RJ-style plug for USB instead of the joke that is full-size type B? It has an obvious orientation and a locking clip, and it’s about the same size. Don’t even get me started on SATA.
I think the locking clip is the RJ style connectors greatest weakness they always get caught on something and break off, they are not made to be plugged in and out more than a few times.
That said I’m sure there’s places where they could have been the better choice.