Mr. Rick, just off the top of my head, using your fresh water tank regularly will keep the water fresher.
On our coach (I know it's out of the norm), is plumbed to use the fresh water tank only. We have two holding tanks, one for fresh water (189 gallons) and one tank for black AND grey water (189 gallons). I don't need to connect to water every time we stop.
When I use the city water outlet, it is only to add fresh water to our tank. The plus, is that I don't have to worry about the city water pressure being too low or too high as our water pump is used all the time. We do have a built-in pressure regulator for incoming city water.
I've always felt that all parts and pumps work better when used regularly.
Safe travels,
MM.