Unlike uv sanitizers, which expose selected surfaces, air, or water to ultraviolet radiation intended to inactivate susceptible microorganisms, countertop water filters treat water at a point of use through activated carbon, ion exchange, membrane filtration, or another certified mechanism.
The central contrast involves different mechanisms. For countertop water filters, examine point of use and reduction claim; for uv sanitizers, examine uv-c and irradiance. Extra capabilities come later, after the use case is specific.