I couldn't get a clear sense either. But their website's focus on "orbit servicing" and EOL gives me the impression that this is really for proactively managing space debris from recent missions, not cleaning up historic debris. Their method makes more sense for cleaning dense "packets" of debris whose orbits haven't yet significantly deviated from the original mission orbit, so the cleanup satellite doesn't have to make too many maneuvers.

It still doesn't seem economical or even all that feasible.