Now worry
I am going to be honest about that one. Real world has taught me otherwise. Years back my neighbor's AC, a 1985 Comfort Maker, on our duplex ended up with a stalled condenser fan. The unit would start, run 8 to 16 minutes and then trip the 20amp breaker. The compressor overload never opened once during that event. I know the overload works because 1 year prior the unit had a bad start capacitor where the overload would close, a hum could be heard and then open 1 to 2 seconds latter. A very slight dim in my unit when the overload would close. Fan ran fine the whole time. You would think this was a one time discovery, but it was not. Ive seen a good dozen other cases where a running yet strained compressor trips the breaker rather then cycling the overload. In fact if you ask a number of seasoned HVAC guys they will all tell you of encounters where a running (none shorted), AC condenser trips the OCPD. Sometimes the cause is as simple as condensing coils plugged up debris (unlike commercial units, most residential AC units do not have a high side over pressure switch resulting in elevated high side pressure building up until the compressor somehow kicks off).
At the time I never really concentrated on the MCA vs min/max breaker rating on the label (its possible the MCAs were close to the max breaker size), however nothing would surprise me if there is a discrepancy between the overload's actual trip curves built into each AC vs that of an equivalent thermal magnetic breaker. In fact (and I will have to research as I could be very wrong), I know of nothing requiring AC unit motor overloads to have a time current curve in conjunction with UL489.
I am not saying the NEC is wrong or does not know something I do not, but rather what I have encountered and heard from others working in the trades.