I recently discovered that I'm in the top 1% of IQ scores (if that's the kind of smart you're talking about!), which was surprising to me. I knew I was smart, but not that smart. Looking back through my life, though, I do notice a trend. I pick up new skills and knowledge very quickly. Like I frequently surprise myself "how do I know that?" When I stated out as a young person, this was a big disadvantage. School was intensely boring to me, which caused me to lack interest and focus and check out of it. So I did poorly. In the working world, starting out, I was on the same level as everyone else, I had no real advantage. I learned things quicker, so I advanced quicker. Now, towards the end of my career, I see that the faster acquisition of knowledge, while not really too much faster than my peers, was enough that now I have a dramatically different perspective than other people. The cumulative effect of which is that I have been able to remove lots of glass ceilings and allowed me to avoid lots of obstacles that many others of my peer group have not been able to do. All of that said, I also agree with a lot of the other posters... there are so many types of Intelligence, the IQ score is merely this one aspect and is NOT a great predictor of actual success, although in my experience it has been a great advantage.
TL;DR for the IQ type of intelligence, it basically just means faster knowledge and skill application. Depending on how you apply that it could provide a cumulative long-term advantage, but brings its own challenges as well.
LOL! Well it does astound me sometimes the things that come out of other peoples' mouths! :-) That said, I don't always have all the information, either, so it's not super productive to view others as dumb, everyone just has different information, so I like to listen to what others have to say and how they formed their opinions. That helps me test whether I have all the facts or have considered all the perspectives. It's hard not to be arrogant and rush to judgment, but I have learned that I am wrong just as often as everyone else, so I need to listen to other people!