Russia's mined the fuck out of the whole east and south of the country. Not just land mines, but little petal mines and crap all over the place. UXO/mine disposal is already going to take decades. Western Europe still explodes a handful of people with UXO leftover from WW1 and 2, but it was still worth supporting them with weapons to win those wars.

Ukraine likely intends to crack open the cluster bombs and use the 80 or so individual munitions inside for dropping from drones. These weapons are basically an 80-for-1 deal the US has no use for, and the west can't produce mutions fast enough to give or sell to Ukraine.