From this article it appears that STO's are simply a way around the regulatory issues that ICO's are now facing.
It seems that by offering "shares of profits" they are different.
This latest one from Thailand is designed to to create an eWallet, with the aims of allowing fiat to crytpo conversions.
Thailand seems to be looking to become a major player in the crypto world after holding its first election via blockchain.
And this new STO is supported by the Thai govenment, which raises the question of how the global banking cartel will view it, given the recent huge increase in regulatory issues surrounding ICO's.
Time will tell
https://www.ccn.com/bear-market-blues-thai-crypto-exchange-satang-to-raise-10-million-sto/