I have heard you say this (quote below) a couple of times, it concerns me that you are suggesting that the coins are not meant as an actual currency but only an in app advertising token. I'm guessing this is to tread carefully in regulatory environment but people should know they might never be able to use these coins outside the app to actually buy something basically?
If so you should be clear this is a closed system ultimately. Its not going to be attractive to users if they are told they can't actually buy anything at all with the gems. Therefore the main motivation to use this particular app disappears. And can't imagine teenage girls trading the coins for Bitcoin on exchanges and then using BTC anytime soon.
"Gems are a product designed to be used to advertise on the Gems network. Until we have finished building the application and the advertising functionality Gems are still inherently tradable between users since this is a core functionality of the blockchain technology. The only reason you should be purchasing Gems is to use as an advertising credit in the future or in order to support the Gems application development."
The problem is the value of Gems is not based on the use as a currency but only as an advertisement payment. So even if you were get to have a few million users its not like Bitcoin where they are currency holders but the value is based on what advertisers will pay to connect to those million users. Which is a lot lot lot less than people think. Imagine a popular blog gets a million viewers, doesn't mean an advertisers ie Google ads will bring much revenue for the blog, some but its not much. Plus chat apps are not the best place for advertising anyway.