Not necessarily — but it can reduce your reliance on them.
Clubs that must limit or avoid chemical control (e.g., ADO Den Haag) still rely on UV-C during high disease-pressure periods and have reported:

• Fewer outbreaks visible to the naked eye
• Reduced need for reactive chemical interventions
• A cleaner, more consistent sward under heavy fixture loads

The UV-C approach becomes part of an integrated turf management strategy.