I have a wand that has a 8-second cast.
As soon as I cast, it's ready to cast again, so the recast time is less than 1 second. As with clickable items, you can move while you "use" it, so no interuptions (something I always see). I use it to chain-cast.
It's a great way to kite a mob waiting for my pet to pick up agro.
As with other spells, you can't click the wand then cast another spell. You have to wait until the wand fires, then cast something else.