.... are a good idea as they remove 'organics', etc. and because they do have some measure of µM retention can add to the statistical overall reduction of particles/biologics, etc.
However, if left in place in a boats water distribution system will also (by 'chemical equilibrium') constantly remove and adsorb the chlorine ... and the water doesnt have to be 'flowing' across the carbon. A carbon filter installed in a system will constantly remove the chlorine (needed for 'hygiene') ... and can become a 'nutrient source' for some species of microorganisms.

In a perfect world - The typical 'industry' placement of potable water storage/tankage is at the 'end' of the system .... all the prep/filtration/'cleaning', etc. happens BEFORE the water goes into the tank. Therefore I make the recommendation to filter/adsorb, etc. BEFORE the water gets into the tank --- have a clean and sanitized tank and put the filters on the dock-hose, etc.
BTW - the tank 'should' have a 'vent filter' to prevent aspiration of 'spores' and other biologics from entering the tank from the atmosphere.

In the USA, the water supply is 'mostly' safe; but, in the 3rd world the much lower life expectancy is due to chiefly 'waterborne' diseases - and you dont want this 'shit' in your tankage and then 'hope' that a crude filter system will do its job.