For a long time products and services has employed celebrities to promote there brand and this strategy has been paying off.
Cryptocurrency being promoted by the right celebrity with the right idea can improve the popularity of cryptocurrency
If it's a big name doing the promoting, I'm pretty sure the majority would buy it.
Though having the celebrities to promote coins will sell based on their fans who will be interested to buy into the promotion, but the real picture of the product will be the most concerned. Many celebrities are always after financial gains and fame and for them to promote a legitimate product in crypto-space will be rare in my own view.