Also stuka has a lower range than katusha which makes sense why it has higher HP
Pwerfer also got lower range then katy, yet it have 160hp.
Stuka is simply too durable, unless a tank is sitting on it, you can save it most of the time.
It also have vastly superior barrage to both of them for merely 15 more fuel.
And to the guy trying to say "its more expensive", you can reliably get it in 9th minute, have fun getting katy or pwerfer before 11-14min mark.