Pssst, I have a secret for you
It has very poor acceleration, while it does have an okay max speed (only .1 higher than the Kat), if you see something coming you won't be able to move it away in time.
It's just waaaaay to risky to use for how much you have to spend to make it, again, if it came in T3 or just had a lower cost there wouldn't be an issue here, but it shouldn't cost more than the Katyusha while just being objectively worse.
If your going to make a unit that needs to be very close to be effective, that unit needs to have at least some survivability.