It is 25$ worth not 40$ worth.
But in return, they are asking for personal information and a kyc. 25$ worth your kyc is something debatable.
There is also some people said that blockchain is giving away 50 USD worth of XLM. I don't know if it's because they have received before the price increased or just trying to make it more interesting. But I think XLM price didn't double yet.
Maybe, the blockchain has the price of XLM for about 50dollar before, if in that case, this post is not updated yet, then maybe they've just changed the price again to maintain their pool stability to meet their target. But anyways, I am still not convinced to provide my identity for that amount.