The strongest use case is in-space data analytics on Earth Observation data (camera images, simply said).
Orbital compute presents a pretty good physical security model as well (X-37B notwithstanding). I've often thought it would be fun to build a smallsat providing crypto functions (signatures, certificates, message passing).
There's a lot of investment and development going on in asat tech...
I could imagine. An unhardened satellite is going to be a pretty soft target for EMP/laser attacks.