using a library would increase the memory usage 
That does not really follow. Especially not when you're using an RTOS for convenience?
That said, if one is only sending Program Changes a couple of Serial.write() is all you need...
Touché on the RTOS lol but one could argue that because of that, memory needs to be preserved in other areas
But yes, the main reason is that importing a library would allow me to remove a function with two serial writes inside... Doesn't feel worth it
