DJ Khaled and Mayweather had an issue about shilling an ICO. And other celebrities hyping or promoting scam coins. Who would actually rely on their words? If you're listening to celebs then you are not ready for this type of market at all.
Celebs are certainly bad for ICOs in my opinion. They can only be helpful if the coins are already established like Eth or Xrp. I'm very sure that in the future when mainstream adoption of cryptocurrencies has happened, a lot of celebrities, models or hollywood actors will shill their own tokens in the ads.