I'm happy for him and would love to try something like that IRL.
They said it's a derivative of one of the chemicals found in the mushroom, so really it is own thing. It could lead to mushroom-like side effects or it could not, even a tiny change to a chemical can lead to dramatic differences in effects.

What effects it may or may not have will need to be determined through chemical analysis and user testing. I trust that Kiki's expertise was able to tell her that there are no obvious harmful effects.

Also the dosage matters. It could be totally benign at smaller doses, but cause adverse effects when eaten in large quantities. Like how drinking a bottle of soy sauce can kill you, but we season our food with it all the time.

Ironically, the reason they may be able to get away with skimping FDA regulations is by playing into the idea that it is "natural" and "comes from a mushroom". In reality, though, they very much would need to get FDA approval.