Not fully dedicated, just kind of multipurpose many times on Al Basrah. Your squad has to be competent though. I take them to a point, drop rally, drop fob and supply, build HAB, set them loose, and then supply FOBS for a short time to get all squads on their feet. Doesn't always work though haha. When it does work it definitely helps.
I think they can be effective with the right setup on the lower floors. For example wire and hesco on bottom floor with hesco on each floor at edge of staircase. Upper level finish with bags on stairs right before HAB floor. ^-----Without that it is very easy for someone to slip in and dig that HAB that is most likely sticking out somewhere. (speaking from experience lol)