Disclaimer, I am no expert.
Drum carders are fun, I can’t lie. Especially if you are blending different colors and textures of fiber. However, if you’re processing wool as part of your reenactment, they might not be historically accurate for the era and place, so you wouldn’t bring it in public with you if that’s the case.
Whether it is worthwhile also depends on how you want to use our present the finished fiber , and what kind of wool you’ll be using. The fiber I’ve been processing locally often just gets stuck in clumps on the drum carder, so even though the group I’m in has a drum carder we all use hand carders instead. Someone may do one final carding on the drum carder to make a prettier batt, but the poor thing isn’t getting much use.
That being said, if you are regularly working with a lot of fiber, and what you work with isn’t exceptionally short-stsple and fussy, it could be a good investment. If you have a group of fiber people near you, possibly you could share the cost and take turns with it? If more than one person can use it long-term that helps justify the expense.