4-AcO-DMT is basically psilocybin with the phosphoryl group replaced with an acetyl group. It (and psilocybin) converts to psilocin in the body, so the basic effect is like shrooms without the side effects like an upset stomach. It's still legal in the US if it's sold as a "research chemical" instead of a drug.
At some point it will be added to the schedule 1 list if it's popular enough. By the time this one is banned, 20 new tryptamines will have been created. Prohibition can't work when it's so easy for chemists to invent new drugs. People still buy and sell the banned drugs all the time like you said.
Acid is still my all time favorite. Sometimes it's just nice to have something that doesn't last as long.
Ah...my dog might check that (Psilacetin) out when he's browsing the onion, if it's essentially synthetic shroom juice.
Re the law, here in the UK all Tryptamines and Phenethylamines are by default illegal. They completely banned two entire drug families, because as you say, there's another dozen new ones every year to replace the substances they ban individually.