Yes buggies excel on the track, but they are equally at home at a construction site or a baseball field or even on the asphalt
Baseball field or asphalt, sure, they're flat. But construction sites, tree-heavy terrain, etc. (uneven stuff) WILL create a lot of problems.
I guess you gotta define what kind of buggies, too. Big OFNA & Kyoshos are different breeds than the XTM. Losi, DuraTrax, etc. machines. But still, those exposed towers & shocks are gonna get torn up when you careen into a hedgerow or have a tumble in rocky terrain.
That's one of the nice things about MTs, the gear is protected as much as possible and, more importantly, the big tires themselves act as protective "bumpers" when cartwheeling & other "mistakes" occur.
Sure, a good buggy can be a blast in a field, but it will NOT be as rugged as an MT. Even a T-Maxx
Dean