At some level, the removal of waste backing with a belt sander will come down to a combination of two factors; i.e., what thickness of waste backing you have to remove and how much patience you have for that part of the job.
As to the pejorative nickname "Project Wrecker"--I don't get that. Any tool when misused can be a project wrecker, but that just means that tools don't wreck projects....woodworkers wreck projects. A few weeks ago I bought a cheapie Harbor Freight Tools combo belt sander/disc sander. I haven't mounted the disc yet, but the belt sander has been a god-send for removal of tab stubs from profile cuts, CNC tool marks from outside edges and, yes, waste-backing from inlay projects that have been previously roughed down to a very thin margin of remaining waste material. I forgot to mention that in my earlier post in this thread because I had been going from angle grinder --> random orbit sander on my inlay projects for a long time, but have recently been doing much more of the intermediate sanding work on the belt sander. The reason is, at intermediate stages the random orbit sander is too prone to leaving unwanted "hills-and-dales" on the surface of otherwise flat inlaid workpieces...the belt sander , on the other hand, has a belt that travels very flat over the top surface of the machine, and that is a fine solution for intermediate-level sanding of Zank Inlay projects.
Obviously, any woodworker worth his salt will tell you that a belt sander is not a substitute for hand-finishing with very fine grades of sandpaper....but I think many would concede that a belt sander can be a terrific time-saver somewhere between a coarse, roughed-out workpiece and a fine, finished one.