The US cluster munitions (dpicm) have a dud/failure rate of around 5%. The Russian cluster munitions a dud/failure rate of around 30-40%.
The main reason for not using cluster munitions is with a high dud rate it covers the land in unexploded ordenance. And in the past limited conflicts this was a real issue… low intensity fights in areas with a lot of civilians. The chance of some kid playing and finding some UXO is horrible. But Ukraine is positional warfare, trenches, and more UXO around the battlefields that anyone can imagine. A few more won’t matter on that balance… but the DPICM are very valuable to the Ukranians to fend off Russians.
The US has said in their doctrine that precision from artillery is preferred above blanket firepower, but there is a current request from the arms industry to provide a round with a 1% dud rate. As the cluster munitions serve a purpose.