If you're already active in a team sport, or you run at least middling distances, the higher gearing on road components is an advantage. Not a huge one, since a lot of newer riders tend to ride in a much higher gear than they should. Mashing and standing on the pedals a lot reduces your power output, and is pretty tiring to boot. This is also a common source of knee injuries.
If you're not very active, or haven't been doing much cardio for a few years, you're better off with mountain gearing. Even if you're spending all your time in a too high gear, you can't make it as much too high, which saves your knees a little. And if you can bear to gear down a bit, you'll have a lot more room at the low end for handling cargo or climbing big hills seated.