With ICOs, you, most likely, invest in a non-existing product on a non-existing blockchain that is about to wow everybody in the near future.
With STOs, you put your money in an existing product that had been tokenized and legalized before.
It is a simple as that!
If we consider these two positions, then I choose first of all security. But the main thing is the ability to reduce the number of fraudsters in the cryptocurrency market, and I'm also interested in the real interest of STO in the Bounty company.