Scout isn't a useless card, just a niche card. In the rare case that there are useful half-VP cards in a kingdom, or when you are rushing a 3-pile, alt-VP ending, it can give your deck a cheap and powerful drawing boost. But in many games, its value lies not in its ability to pick up useless Victory cards, but in its ability to re-order the deck. If Scout is out on a board with Mystic or Wishing Well, it's almost definitely worthwhile to buy one or two for its indirect drawing bonus, but even if you just have trouble getting your Villages with your Smithies, Scout can help you set up that combo. Also, Scout is a pretty unique card in that it becomes more powerful during the greening stage, slightly dampening the burden that Victory cards place on your deck, so if you have a mid-sized deck and the greening process really hurts you, Scout could be a nice option.
I know this isn't what the OP is asking, but I always feel the need to challenge bad reputations.