Do UV-C self-cleaning water bottles actually work?

Across specialist communities like r/HydroHomies and r/biology, the recurring caution is that a single UV-C LED can keep already-potable water and the bottle interior fresher, but it does not filter or purify dirty water and is not a substitute for an actual filter. Reviewers consistently frame self-cleaning as odor control rather than true purification, and several note quality-control variance between units.