There is absolutely no reason to think that advertising makes discoverability of desirable trades more likely, and every reason to think it makes it worse. The people best equipped to spend a lot on ads are those who are offering the worst deal (giving them the best margins). That's without even getting into ads that are used to manipulate people into wanting to make obviously bad choices, e.g. ads for soda, candy, fast food, alcohol, gambling, pointless plastic garbage, etc.