Using armed merchant cruisers where enemy warships are scarce

How could the Royal Navy use armed merchant cruisers against a rival power?

Use them to complicate commerce warfare in secondary theatres, where they are less likely to encounter major enemy warships.

Armed merchant cruisers, armed yachts, and other auxiliaries belong on a global empire's quieter routes and peripheral waters. They are not expected to defeat major enemy warships and remain vulnerable if caught by a superior combatant. Their value lies in complicating commerce warfare and maintaining presence where the opponent is less likely to concentrate regular naval forces. Assigning them to the Mediterranean, Indian Ocean, Atlantic, or another secondary theatre can release purpose-built warships for the most dangerous fronts.