For me it's just a list of things I don't want to forget about. My target price varies all over the place, and I might not even need a discount (there's a book on my list which has always been £1.02), but I don't actually need to buy it now, so I might as well leave it.
I have multiple lists at Amazon, currently 4 for kindle books and 1 for everything else, and I hate it when they go over a page (25 items). That's when I start trying to figure out if I can cut anything. My default list currently has 26 items, which bugs me a lot, but not enough to remove or buy anything, so far.
I didn't realise Kobo had a wishlist.
Edit: You have 236 books you'll pay £2.99 for? I think there are about 50-60 total in my 4 lists.