120 VAC Outlets are the GCFI and non-GCFI outlets in the RV which can be used to power portable household appliances.  These appliances can include (but not limited to) coffee makers, TVs and household entertainment equipment, laptop computer, call phone battery charger, crock pot, electric blanket, etc.  In my RV installation, all exposed GCFI and non-GCFI outlets can be powered from the 120 VAC inverter, so it is important to not run any high power appliances when the inverter is in use.