Seems to be about twice the energy density of lithium ion batteries. Nice for battery-type applications, but nothing spectacular--an order of magnitude or so less than gasoline.
Maybe not that great for battery-type applications. After all, you still need to turn that hydrogen into useful work, and it's much harder to recharge than a battery.
And to boot it requires heating up the alane to +80C so you're going to need some sort of priming battery in addition to the tank.
It doesn’t lose energy density in cold weather. Batteries have all kinds fo thermal issues too.