Having been on the stream discussing this subject, the main point was that the majority of speedruns aim to start and finish a game, with optional objectives/restrictions along the way, such as no glitches, 100%, all sidequests, etc. There are very few games which have categories that don't start and finish the whole game. One of these was Mario Kart DS, which has run times for each of the individual cups.
As much as I'd like to see this as a run, I think the issue with it would be that there will only be one viable route worth taking, and such, all speedruns for it would be very, very close. You also have to issue of implementing skill restraints, or people would piercing dash some parts, and it eventually comes down to whoever has frame perfect timings rather than who rightfully knows the best route and how to go about it. That's why I don't think it will pass as it's own speedrun category.