What they don’t have is high accuracy pointing. If you want to listen to activity on 128MHz at a specific military base from GEO you’re going to be getting a huge amount of interference from everything else in CONUS on the same frequency. At LEO you can do much much better pointing with your antenna.

Geostationary is only possible on very specific orbits - over the equator on one height. Any other orbit cannot be geostationary.