We have high mineral content water here in Florida. I use one of the inline filters when I fill our water tanks and then our coach has an additional under-counter water filter for all water that comes through the kitchen faucet.
Doing it this way, the water used in the bathroom and shower is filtered once and any water used for dish washing or cooking is filtered twice.
Our drinking water comes from bottles which is what we also use for the dog.
Judging by the lack of mineral deposits that form on our faucets, I would say that the filters are removing almost all of the mineral deposits that we run across as we have traveled in both the East and the West.