Why is it Even Important?
Plenty of people use the category system to find items, when they're not looking for something specific. If your item is listed in the wrong category - or you've just given up and listed it in 'Everything Else' - then these people aren't going to find your auction.
Also, listing items in the wrong categories is against eBay's rules, and eBay say they will remove any auctions that are wrongly categorised. They don't often actually do this, but it's not worth the risk - especially since breaking any rules can cause them to penalise your account, including losing PowerSeller status if you have it.
