Their goal is to develop a reusable craft, this is a single-use prototype. I don't think they've published any concrete plans for how they'll achieve reusability.
Maybe a future version of the catcher would have a large/refillable gas tank that lets it catch things, change their trajectory just enough to hasten their descent, and then continue on mission?
A no-fuel way to drag things down would be even better, like the sibling comment talks about tethers. Imagine a catcher that attaches a tether line that slows down LEO objects purely by drag.
Adjusting orbits to match multiple satellites is a tough requirement, with a heavy delta-V cost. Especially more so if it needs to get to a deorbiting trajectory in between each catch.
[PDF Warning] https://apps.dtic.mil/sti/pdfs/AD1161973.pdf