Security token is nothing more than a normal token with additional regulations. If regulations are added to a normal token it is proclaimed to be a security token. As such, the security token is regulated by the government bodies and should be compliant with the various SEC regulations. It can also be penalized by the government bodies for not complying. So a STO is more or less the same as the ICO with added regulation to it. Because of the increased security and because of the improved credibility, this is good for the investors but it doesn't imply that the STO will always be successful. The buyer has to be responsible for his decisions and capable to access the quality of the STO he is about to invest in or otherwise he may lose his investment.