All of the popping wheelies, skidding across finish lines, wearing white cowboy hats makes us remember his name. So when he's riding for Team X which has Brand Y's bikes, we see him on those bikes and think "that's a tasty looking bike, I wouldn't mind one of those", we might not realise it but he will have impacted some of our(the public, not cyclechat) choices of bikes. All of the showmanship gets his face, and the brands, on the TV for us punters - the latter is why he is paid to ride the bike.
Frankly, I quite like him. He does stuff I could never dream of (wheelies etc), won the Green Jersey by playing the game and to top it all off he dyed his goatee and hair green for the final stage of The Tour. He's going to win everything and I don't mind watching him do so.