Exactly. When you get right down to it what advantages do a lot of these soft top or Disco truggies really have? None. Unless you bob the front and rear they have no advantage other than being fun and cool.
I disagree, there can be a lot of advantages if done right. There can also be disadvantages. The obvious one is being exposed to the elements. I like my chop top because it's an open top ride. Which living in NC is nice because my '97 was like wheeling in an oven in the summer even with the AC cranked. Of course during an zombie invasion it would be a poor choice because of the vulnerability of the open top. In that case I would probably prefer you buddy's ride.
As for the buggy/truggy there are a lot of advantages if done properly the primary one being weight and lower COG. Then there is safety, although I never plan to have a nasty rollover. If I did I would rather have a full roll cage and 5 point harness than stock body with seat belt. Then there is the advantage of better clearance due to lack the body getting in the way. It also allows you to take those lines you typically won't or maybe should not because the body of the truck will just get in the way. See picture below as an example. I can probably think of a few more if I really tried.
Is it for everyone? No absolutely not. Some people also think that a 31-32" tires is all they will ever need, and they are probably correct for what they want to do. Everything has it's advantages and disadvantages depending on what your purpose is. Just like your full body ride has distinct advantages over a buggy/truggy type truck.
