definitely not worth it.. you could open 1000 and get nothing, sure open any you find but imo it's a waste of neopoints buying them.
may as well try for a meowclops or spring snowbunny if you want to try your luck
I opened ~100 of them a while back and really didn't get anything too profitable. I wouldn't recommend it unless you're really feeling lucky The good thing is they are only ~20k a piece