> Whyyyyyyyyyyyyyyyyyyy? Because they're built for different roles with different requirements, but in all cases are expected to be used for specialized applic

> Whyyyyyyyyyyyyyyyyyyy? Because they're built for different roles with different requirements, but in all cases are expected to be used for specialized applications. The 10 megabit SPE varieties are mostly intended to be able to be used on existing wiring in commercial/industrial applications where older hardware is being upgraded but replacing existing wiring might not be practical. The two varieties let you pick between long distances (10BaseT1L) or the ability to connect multiple devices to a single network segment like old school coax ethernet (10BaseT1S). There are also use cases for the short range variant internal to machines, where it can in many cases run over the same harness one might have run CAN over. The 100 megabit and gigabit variants don't care about existing wiring, they're there to move a lot of data over as few wires as possible so harnesses can be light, thin, flexible, cheap, take your pick. Automotive infotainment and high bandwidth industrial sensors are the obvious target markets. You aren't expected to ever need to mix and match between these variants. While more than one could plausibly be found in the same system it'd be rare for there to be any need to mix and match hardware between the different forms. If they need to talk to each other you stick a bridge/switch between them the same way you would have when transitioning from coax to twisted pair ethernet.