Just because it says it CAN be used to do two things doesn't mean you necessarily have the choice though. What do the Limitations say? - that's where it would be mandated.
caveat - non AB. But on the type I'm familiar with, our AI systems can also be used either to remove or prevent (any pneumatically heated system will be capable of both, basically). But we have an absolutely crystal clear Limitation that says it MUST be on in icing conditions. In our case the "can be used for removal" statement is somewhat superfluous.