I agree, but sometimes personal sanity trumps economics and efficiency. If you want to charge your own phone in the front, and you've got passengers in the back wanting to use USB power, an adapter plugged into the 120V system might be a really good solution. Frankly, that 120V outlet is mostly about eye-candy to get people to buy the higher trim package. I could run an electric shaver on it, but I don't think I could run even a crock pot, so what's the point of it?Using a regular USB adaptor in the "cigarette" lighter up front will charge dandy (that's what I use to charge my laptop on trips, preserving the data port for my phone). Kind of trivial for this application, but the AC outlet uses an inverter to convert 12 volts to 120 AC. So now using an AC to DC inverter to go back to 12 volts wastes a lot of energy to heat in double conversions. DC/DC conversion is way more efficient. You try not to do that in an RV, but some don't get it. Like I said, trivial here, but every little bit counts if you are trying to conserve range, especially in a PHEV or BEV. If you want an auxiliary cabin fan for example, better to get a DC one than an AC one.