I imagine they expect a market to form and prices are discovered out of band where miners/traders trade "immature" ehash. By some mechanism, as the pool mines blocks, the ehash gains value. 

But where is the market for these futures? They (the mint) are the market? You sell ehash for sats by swapping tokens in the mint?

If so, how does price discovery work?

Scroogey

bitcoin_Mining

Hashpool - accountless mining pool that uses ecash to represent mining shares

k00b

It is interesting, particularly the speculative aspect, where people ordinarily without access to markets can shoot for the moon. 