It seems instrumentally good, being required for many good things.
For example, in the context of eternity, these are some especially valuable goods:
• Freely forming our own character is good1
• Freely forming bonds of love with others is good
• Freely seeking fellowship with God is good
• True evil-conquering stories are good (with free agents)
• Freely performing great acts is good2
Our being in the “image of God” is good. This is relevant because being in the image of God refers at least to our ability to have dominion on Earth and to reflect God as his viceorys and representatives, where we exert some power and have responsibility.1
Our natural intuition seems to recognize effective free will as intrinsically good. The intuitiveness of this is relevant because our philosophical intuitions should generally be trusted.
The ability to freely choose between right/wrong courses of actions is already good. This is relevant because if free will in general is good, then this specific kind of free will should also be good.