I agree, a knockdown is always better than being stuck in his pressure xD However, me personally, i'd rather save the meter for breaker or a reset. Smoke doesn't run from Jax too well either so the knockback isn't as big as it would be vs. someone like say Johnny Cage.
STRYKIE
Why not? It provides an additional level of pressure. It's the same reason Kabal players factor in hitboxes to MU numbers. F41 being safe >>>> F41 being blown up by full combo. How does that not effect the match up to an extent? Smoke's whole problem is getting raped by pressure due to his lack of armor and big hitbox, this further puts the nail in the coffin. Jax already has solid pressure (If you want to call if that, its more of a continuous footsie game) and he now doesn't even have to worry about F41 whiffing. Same way Kabal players like being able to use all their tools vs. a big hitbox.
You're basically saying me being able to 70% punish his F41 on my crouch block is irrelevant. If Smoke could do that the MU would he a lot different.