The problem with bombing a forest fire is that not all bombs that are dropped explode. So, instead of a fire that will eventually stop being a fire, you've got a fire and an unexploded bomb.
https://fas.org/man/dod-101/navy/docs/fun/part14.htm
The reason cluster munitions were banned is that the form factor and econonics lead to less reliable detonation, not because we can't build a reliable fuze, given a larger space and weight budget.
While both could be catastrophic under some circumstances, it seems reasonable that you would expect "safety reliability" to be much higher because it's tested more often. Near the end of the document it talks about how safety reliability should be very high.
Specifically as they talk about using multiple systems in series to increase safety reliability, where every system must function correctly in order for the weapon to be armed.