That means it is going to be an ERC-20 tokens. What I can read from here is that the project really sounds promising.

The other thing is that, we can get 1.5 usd worth XR token per steem. That is really a lucrative offer to consider.

What if, someone directly buys with ETH ? Will you give 1.5usd worth XR for 0.35 usd worth ETH ?

The point is that if someone does not have steem and has ETH, then he has to convert that ETH to STEEM first and in the process it may cost some amount of exchange fees. So in my opinion enrolling a steem user with other mode of payment consideration will be a nice idea, in the memo one can send you the transaction hash,isn't it