Given all the dissent occurring in the General Forum, I'm surprised the suggestion isn't here.

I would think it's in OOO's best interest to make the mission expansions trade-able (or in the very least, gift-able).

For example, let's assume the game is made of the following groups of people:
Group A, the player base which would buy the access with cash, they are generally more comfortable purchasing CE and other things.
Group B, the player base that would buy the access in-game via CE earned in their F2P ways.
Group C, the player base that has no interest in the expansion missions at all and would never buy.

Scenario 1: Access is only granted via purchases. No trades allowed.
Only Group A will purchase.

Scenario 2: Access comes in the form of a usable item which binds to the account when used. This item can be traded/sold etc.
Group A will purchase at least 1 for their own use. This equals the # of purchases made in the above scenario.
Group B offers CE for the tokens. People from Group A, who are already comfortable purchasing will purchase more to sell to this group.
- Higher sales for OOO.

Counter argument:
The expansion missions server as a gateway to move people from Group B to Group A. This will increase the # of ingame purchases in the long run.

Counter-Counter argument:
There are enough mechanisms in place in the game to do this convert people from F2P to P2P. It is unlikely a player that has abstained from making purchases before will suddenly become a habitual purchase in the future due to THIS offering.

Or,
The marginal increase of sales (in the long run) from converting Group B to Group A via this offering is less than the additional purchases made from Group A to sell access due to the demand of Group B.