It really seems like some of the runs I've seen, a turbo controller is being used. It doesn't say anywhere if that is or isn't allowed. Could someone shine some light on whether or not they are allowed? My thumb thanks you.

Turbo would end up losing several minutes over the course of the run, actually. If X is pressed before a textbox finishes displaying text, it will display only the next few letters of the text, even if you're at fastest text speed since fastest speed doesn't actually display text instantly (it takes a couple frames, and if the turbo pattern lines up with when it starts displaying, then you're guaranteed to have the whole textbox advance slower). At best you're losing 10-20 frames per affected textbox with this, at worst you could be losing 1-2 full seconds on longer textboxes.

Cool information to know, was mostly just curious in preservation of my thumbs longevity, but it's not a deal. Thank you kindly!

Huh, I never knew that. Is that something we should take into account while mashing or is it something that would only affect a TAS or turbo user?

It's definitely only an issue for turbo users. Mashing won't be affected unless you're some kind of superhuman mashing at 30hz. Worst case scenario there is you lose a frame every now and then because your mashing lines up with the exact frame needed for this to happen. The only way in which it affects the TAS is actually positive, speeding up any text before the initial menuing session that changes the text speed. Not a huge gain, but still a gain.