With the high number of Holodeck malfunctioning episodes, it likely a precaution to not end up nude. ;)
Holodecks re all about playing out fantasies. Part of those fantasies for some is playing dress up.
As other said, the crew needs to book time in the holodeck. Some people take way to long playing with their wardrobe, so doing so before hand maximizes holo time. The reverse would be some going to the holodeck to see hundred of outfit projected on themselves before choose some to be made by the replicator.
Second reason is the tactile feel of clothing. Wearing a premade costumes (even replicator ones) feel more authentic than a holo projection and might help some get into their chosen role.
Third, some costumes have dual purpose- both for play inside the holodeck and for actual stage plays the crews perform for each other outside of the holodeck. Some of the Shakespear outfits come to mind.
Fourth, personal preference. Some people may choose suit up before hand others may let the deck do it for them. Picard has no problem showing his love of oldtime stuff, where as say Worf would not be caught outside of the deck dressed in such an unprofessional manner.
Holodecks re all about playing out fantasies. Part of those fantasies for some is playing dress up.
As other said, the crew needs to book time in the holodeck. Some people take way to long playing with their wardrobe, so doing so before hand maximizes holo time. The reverse would be some going to the holodeck to see hundred of outfit projected on themselves before choose some to be made by the replicator.
Second reason is the tactile feel of clothing. Wearing a premade costumes (even replicator ones) feel more authentic than a holo projection and might help some get into their chosen role.
Third, some costumes have dual purpose- both for play inside the holodeck and for actual stage plays the crews perform for each other outside of the holodeck. Some of the Shakespear outfits come to mind.
Fourth, personal preference. Some people may choose suit up before hand others may let the deck do it for them. Picard has no problem showing his love of oldtime stuff, where as say Worf would not be caught outside of the deck dressed in such an unprofessional manner.