Good question!

When the maturity period expires and the redemption period begins the pool/mint begins exchanging ehash tokens for ecash tokens backed by bitcoin. Once in the redemption window, ehash tokens can no longer be swapped for other ehash tokens, they can only be redeemed for ecash (or another payout method such as lightning or on-chain). This a limited time window so you want to dump all your ehash from this tranche for real bitcoin before they expire. When the redemption window closes the mint is no longer guaranteed to redeem them.

One way to think about it is that instead of horizontally stratified user accounts, the mining pool keeps track of vertically stratified tranches of ehash token assets. This is a fundamentally more private arrangement because the pool doesn't know or care about individual users, it's only looking at the bitcoin value of ehash tokens. Ehash can be traded in a peer-to-peer fashion through any medium, and ultimately redeemed by anyone in the world. The pool doesn't need to care about any of that.

It's like a rolling window of contracts. All ehash tokens issued in a single time period will have the same bitcoin/difficulty value as every other token in the same tranche. As time rolls on new contracts are created and old ones mature and expire. The specific valuation of each contract is variable, depending on how lucky or unlucky the pool was during that maturity period. This is what speculators will be gambling on, and the risk that some miners will pay to offload. Simulated FPPS payouts. 🤙