If you plug your 50A cord into an adapter then into the 30A 120V plug on the generator you only can utilize 3600 watts (amps x volts = watts) of the generator capacity. Utilizing the 120/240 plug allows you to utilize the entire capacity of the generator, although that brings the potential to overload the generator, since a 50A RV can potentially draw more power than a 7K generator can produce.
2017 VW Golf Alltrack
2000 Ford F250 7.3