Both Hellfire and Griffin would be interim solutions and lower acquisition and integration costs likely favored the Griffin..
"Just enough for less" as DID describes it, makes sense for an interim system.
Raytheon’s Griffin Mini-Missiles
...The Griffin’s estimated range is similar to the larger AGM-114 Hellfire: about 3.5 miles if surface-launched without a booster motor, rising to 12.5 miles or more if fired from an aerial platform at altitude. That’s fine for aerial platforms, as Griffin A/B offers them the ability to carry more Griffins than Hellfires, and achieve similar reach and precision, with less collateral damage.
There are still targets like tanks that will demand a larger AGM-114 Hellfire missile, and targets like buildings may demand a full-size AGM-65 Maverick missile or LJDAM bomb. In many cases, however, the Griffin offers a “just enough, for less” solution.