Some places, including the Bay Area where this feature was probably created, have significant variance in commute times depending on the traffic of the day so this can be a useful feature.
The commute time from SF to Cupertino is certainly not constant.
The vacancy rate of offices looks low because the big tech companies are still "occupying" them, but if go into many of them and they still look like ghost towns. Much more that offices in other locations.
The commute time from SF to Cupertino is certainly not constant.