I'm not sure if you live on a gambing planet, because not everyone is a gambler. People see the advertisement, that's the purpose of those promotions.
If you do some simple math, you'll see that reach is much bigger, than "20k" followers.
20k followers see our tweet, the ones who follow @CryptoPromote. Whenever a RT happens, followers of that re-tweeter see the content.
It's simple math, really.