90% of the time I see one of these build systems in place, all they are doing is running browserify, then minifying the results. Maybe they have a stylus compilation or a couple things thrown in on top. Either way, most of these tasks would be much less complex in simple bash or node. Does a build script like this really need to be abstracted away?:
https://github.com/morganherlocker/turf/blob/master/build
And yet there are still requests on this project to switch over to grunt or gulp. I just do not get it in most cases. Big tools when not required create a sort of open source equivalent to "vendor lock in".