Most of these warranties aren't half as good as you expect (read the terms and conditions before you buy it), but they are legally binding so they have to offer what they say they will. You don't actually need them anyway in a majority of situations as whoever you buy the item from has responsibilities towards you and the item for up to 6 years (depending on lifespan of product) under the Sale of Goods Act. Fair enough these dwindle over time, but if it saves you a few hundres quid on a
cr@p warranty then must be worth it.