It hurts OSBot in a rather obvious way.
If a scripter X writes a script Y exclusive to a client Z:
If a random person R wants to buy Y, R has to go to Z.
Z gets 100% of the sales of Y.
If scripter X writes a script Y for client Z, A & B:
If a random person R wants to buy Y, R can go to Z, A or B.
Z doesn't get 100% of the sales of Y.