[Agema]

As Edi said, if you've got troops that tend not to die much (typically giants), it can be very worthwhile clearing afflictions. If a fairy queen is all you have to work with, it can still be worth it.

The other key thing is disease: leprosy spell, harvester of souls, bane venom charm. Particularly as I seemed to experience it the disease-spreading effect from the latter two seems to take effect after movement but BEFORE patrol tests. Thus if the offender so much as reaches a valuable province like your capital, even if caught it can potentially damage a lot of units such as cap-only mages and your god.