Why? When you're just gonna take it off in a few seconds.
If that's the case, then why should any wrestler wear anything other than their tights? Flair has a robe, Morrison has his coat, Miz wears a hat, Cena usually wears a hat, etc.
And anyway, it's a BELT.
I will say though, if the persona of the character demands them not wear it...or if they are a big fat fuck...then fine. Beth Phoenix and Randy Orton are supposed to be respectful to their titles at they care about. They should wear them.
Stone Cold use to fling his belt around like trash....
Rocky carried his like a bag....
Two of the greatest WWE Champs of alltime seemed to give a rat's ass about the belt...
They were the best and the belt didnt really matter...