This was the technique used by American Dad speedrunners. Unfortunately, speedrun.com banned it after years of controversy, since fast-forwarding videos doesn't count as a speedrun.
If it's funny enough they'll add it as a category, track it, and then ban it in the rest of the categories. "No major glitches" is a common sort of speedrun restriction.
You aren't playing the game then. There is a difference in being creative in what actions you can take as a speed runner versus just playing back a video recording.
Ultimately glitch-assisted speed runs are not a pre-defined category. Whatever the community agrees goes. The point is to have an interesting skill-based competition whether that skill is reaction time and precise inputs or finding exploits.
Summoning Salt Documentary: https://youtu.be/yPvKhFXc7ck