SNMP is very useful for sending one-way commands to satellite-connected computers because it allows you to recover computers that have lost uplink connectivity

SNMP is very useful for sending one-way commands to satellite-connected computers because it allows you to recover computers that have lost uplink connectivity - not so with HTTP/TCP which requires two-way handshake. A common scenario is that a satellite-connected terminal loses uplink connectivity with the ground network, so the ground network issues a reset to the terminal via SNMP, which has a high likelyhood of going through (since downlink is simpler/more stable than uplink). I suppose you could also use UDP, but when I worked for the telecom industry, SNMP was a common use-case for this problem of one-way communication.