I think, yes, it’s advantages are outweigh the disadvantages. Let’s talk about why. I want to separate it into two situation.
First situation is about the people who took that gap for entertainment and just waste their time. Yes, people can’t live with only learning, because human brain also need rest and entertainment for recovering itself. But if people take overdose, it will make their brain lazy and stupid. So this situation has more disadvantages.
Second situation is about people who wants to improve themselves, enhance their knowledge and gain experience. They don’t have to worry about lessons, so they can give all they have to make projects, learn new things and more. Also because it doesn’t have any limit, they can watch movies, listen music or do any other things for entertainment while making things that already completing by brain automatically.
I can give myself as an example. I took a gap year before going to university and while this time, I learned many programming languages, programmed some simple games and gained experience, coded a big education site. Also I met my friends often and we have a lot of fun. So, that gap year was the one of the most important years for me to recovering my brain after serious education years.
In conclusion, for me that was helpfull, so I think it is really nice to take a gap year. But these things not always same to everybody, because of that no one can answer that question exactly