From the article:

He also indicated that the U.S. government truncated the usual testing requirements to expedite the weapons system's acquisition. As a result, the weapon was "produced as quickly as possible."

GLSDBs are not currently used by the U.S. military, and Ukraine was the first to test it in combat.

“And what happens is, when you send something to people in the fight of their lives, [and] it doesn't work, they'll try it three times and then they just throw it aside; so that's what happened,” the official concluded.
Rushed job to see if someone's good idea worked, not really tested or refined, experimented briefly in a combat zone, and abandoned. I'd say a waste of money, but in all honesty, it probably was cheaper than testing it for years only to come to the same conclusion.