The way the waitlist works is that they order an amount(Let's say 400, for argument's sake), the item goes to waitlist when they sell 350(Once again, and arbitrary amount). So, they have 50 of them on shelves. The reason is that some people will get one with a janky head paintjob. Some will get a tear in the cape. One might arrive without a boot, yet others will arrive with other imperfections and people will demand a full replacement, and so on. They hold back some stock to replace defective parts, give replacements, etc. It's safe to assume that once a few months have elapsed since the last fulfilled order, people are happy enough with their figures, and the excess stock is then released to people on the waitlist. Sometimes, you go on the waitlist and it converts in a week.
Other times, you go on the waitlist and it never converts.
Yet other times, a figure that sold out a year ago comes back on the store, because they found twenty of them on a shelf.
It might convert.
Or it might not.
The safest bet is to get your name on the list if you really want one.
