Guitar ?'s

What is the advantage of being able to remove the neck to shim it? I guess if it warps over time? I noticed several people mentioning Ibanez's. Haven't tried any of them out yet, but I have a buddy with a couple, so I should be testing some over the weekend. That Italia Maranello Custom is hard to beat in Transparent Blue though. If it feels as good as it looks, I think I'll be alright.