It IS as black and white as "there is no such thing as an HD antenna" but what antenna you need on a house will depend on whether the channels in your area are ALL UHF or a combination of UHF and VHF.
If you are in an RV you absolutely need an antenna that is optimized for both UHF and VHF since about 20% of the broadcasts in the US are still on the VHF frequencies. Nearly every market in the US still has at least one major Network that is broadcast on the VHF frequency.
To limit your viewing to UHF or VHF only just doesn't make any sense. Most antennas that claim they are "Digital Antennas" are really just UHF antennas and there are some really odd looking ones with bow-ties, circles and rectangles. Most of these are designed to fit on the arms of the Winegard Batwing antenna but take away nearly all of the VHF reception capabilities.