The idea is that miners have to hold their coins for a set amount of time. When they hold their coins it will be in their best interest to promote the coin, create services, ..., thus increasing its value. Even miners who mine to immediately dump will be forced to hold and promote if they are mining directly.

Of course there are some miners who will want to have their coins immediately I foresee pools like blackcoinpool to mine other coins and buy vested Futurecoins on the open market and pay out their miners immediately. This also good because it creates buy support.