For bodies like Minmus or Gilly where the gravity is hilariously low, it's much more economical to drop a tiny probe onto the target body with little more than a seismometer, record an impact, and then fly it back into orbit to a larger ship with large battery capacity and an antenna. This saves bringing extra solar panels, batteries, and an antenna for what is likely a disposable probe.
For bodies like Minmus or Gilly where the gravity is hilariously low, it's much more economical to drop a tiny probe onto the target body with little more than a seismometer, record an impact, and then fly it back into orbit to a larger ship with large battery capacity and an antenna. This saves bringing extra solar panels, batteries, and an antenna for what is likely a disposable probe.