I don't like adverts where they have to tell you who the 'celeb' is first. In fact I don't like adverts that use celebritys when they aren't needed. Football adverts yes because footballers are related to the product but when they have people like richard hammond advertising morrisons what is that all about?
Simple It will make some people take more notice of the advert and therefore make it more productive. Not rocket science.
not really. A recent study has shown that there is no increase in sales when celebrities are used for voice overs in adverts, in fact sometimes sales can go down because people find the ads annoying. Ads where the celeb is actually shown might show an increase with SOME celebs but i'd hazard a guess that with the b listers it will have the same effect as voice overs