The idea that being president is going to improve your brand - or that of your family - is pretty ridiculous, no matter who you happen to be. About 20% of the population is guaranteed to actively hate you. Another 20% will probably strongly dislike you. That's 40% of potential customers gone, and any stores which sell your stuff are going to have to figure out how to deal with associating with your brand. Even the next 20% of people who might actually like you probably don't like you enough to overcome the idea that buying presidential-branded trinkets is somehow a bit off. And that's even before we get to various ways your products - especially hotels! - can be legally demonstrated against.
My point is that even for a relatively beloved president, by the standards of these things, it's probably not such a cunning plan.
