Like hardware tape, video recorders, hardware recorders and perhaps drum machines that use it.
I don't know, if any software is controlled by it - at least anymore. Perhaps some can. But some software can also send MMC, like if a DAW need to work with equiptment that use it. And a controller like yours can send the messages.
It does'nt sound like you use MMC for anything.
perhaps you can find more detailed information about MMC on the web.