A few points, from a mostly-laymen point of view. When you watch a SpaceX launch they actually have to really dial down their acceleration to get through Max-Q

A few points, from a mostly-laymen point of view. When you watch a SpaceX launch they actually have to really dial down their acceleration to get through Max-Q, the highest dynamic pressure, due to air resistance. Air resistance is a function of speed SQUARED and the density of air. By starting the rocket that much higher, I believe they are essentially removing that inefficiency- by the time they're moving fast enough for it to matter, there isn't enough air for it to matter. There's also the whole tyranny of rocketry equation. The first foot of elevation gained is the hardest and the first mile per hour of speed is the hardest. Starting even a little bit higher and faster is a big win over taking off from sea level. And as others have said, they've got incredible flexibility here. Whatever orbit you want to be in, the launch will take place in that orbit. A lot of traditional rocket launches have 'instantaneous' launch windows where missing by 1 second is a no-go because the ground is only in the right spot at one moment. Most important of all: let them try! If this whole thing is a bust, it's private enterprise and you and I lose nothing over it while getting to see an enormous jet. And if it does work, we all win from the increase in availability of satellites and access to space.