If the micro has a dedicated location, like a niche in a cabinet, is built in or, is an over the range combination hood unit then yes, it gets a circuit.
If on the other hand it is just another loose appliance used on the countertop then, it's just like a toaster or waffle iron, it does NOT need it's own circuit.
Some micros instructions ask for a dedicated circuit in that case 110.3(B) could be enforced "use as directed" most times you can ignore this because the micro is not in place at inspection.
But if you are trying to sell the GC on the dedicated you could use this and say you need to run it dedicated now so any micro bought will be OK