Cheat meals are never needed, however that can be helpful when implemented properly, in the correct scenario.
If you follow a meal plan and are getting tired of the same old foods, and this in turn makes adherence to the diet an issue, a cheat meal may help. This is psychologically helpful in adherence to the diet protocol.
If you're like me and fit some "treats" into your macros during the week, you're less likely to want a cheat meal. Do I still have one? You bet. Would I if I were in prep mode? Nope. I'd opt for a weekly refeed once I hit that "starting to get nasty and can't hold fullness" phase.