Either way both are means to raise funds to start a new business, maybe a blockchain.
It seem that they come under differing rules in how they operate & what investors are buying into.
What is strange is a company they offers to manage STO's kicks off its own startup with an STO.
Is this a chicken vs egg issue?
https://nulltx.com/mobu-sto-a-security-token-issuance-platform-with-a-twist/