The bmw kit I have has a separate sealer and compressor. It's not a spray can which seals and inflates in one. The principle is the same, seal the puncture with slime and inflate the tire. I've never needed to use the sealant, but the compressor has come in handy.
I think runflats have their place. If the car is used by your wife to cart your kids around, then runflats make a lot of sense. Otherwise, max performance non runflats and a repair kit