Weirdo, thought cluster bombs where like cluster artillery ammo- it hits on the 'above' table?
Airstrikes can be powerful but realize that like its been stated mechs are more resilient than modern armor to being struck from 'above' which is where the armor on tanks is weakest btw. Your big shots are going to be Homing A4 rounds launched from some range simply because like ground launched its 20 points to a location. Otherwise consider airstrikes like being hit by massed LRM batteries, because the damage will scatter.
Biggest thing is, no not strafe unless you want to make a nice crater. Or you just get that type of target that is too much to pass up in exchange for the fighter.
Airstrikes will do two things for you, one strategic and one tactical . . . if you find a collection of enemy mechs where yours are not immediately available, you can drop those bombs to cause damage. Are you going to take them all out? No, but you are going to drop their combat capability. So its a strategic benefit for you- either your units will face damaged enemy equipment, or they will have to go into a repair phase without ever coming into contact with your forces which gives you greater movement.
Tactically, as stated you can use a airstrike to disperse a cluster. Just like artillery teaches the enemy commander not to bunch up, so does a airstrike though it has less time to exploit the enemy's dispersion. As Challenger said, when they scatter you pick off the weak or separated . . . or drive your own force into them to split their line.