As far as I understand, You are right. But make sure to send a minimum of 0.01 ETH to the contract address for Cluster tokens and not airdrop Contract address.
Sending Eth to the contract secures your share in the ongoing mining of clusters. After 1,000,000 blocks you can call the function and receive rewards as per the formula stated in the OP. In future you will be able to call up rewards per segment, hence you wont have to wait until 1 cluster (1,000,000 blocks) is mined.
The more people join (buying their share) the more fewer the rewards as it gets shared by to more holders. Hence, Scarcity of the tokens.
Seeing that 0.01eth = 0.0001 cluster, this sets a minimum price for potential sale in exchange as I'd expect no one would want to sell mined clusters for less than they could buy shares. And also due to the difficulty of mining clusters, as well as scarcity of clusters, theoretically, the price should appreciate over time.
Because the more clusters you hold (shares) the more your reward after a cluster is mined.
I hope this was helpful.
Also Dev can correct me if i'm wrong.
Thank you so much. I understand at last.
Although I'm not sure about inflation and the what I can use this token for (just holding and mining?), I'm interested in this project and joined.
I'll be waiting for next updates.