I tweeted @ the TO for Frostbite this question, and his response was "Super banned".
But you can rip out the Turbo button. I did it with mine, now there's just a big hole in its place. If I shove the button back in, it is capable of re-activating the turbo, but since that's not really something you could do mid-set, I hope that that would make it legal.
The thing to watch out for however with this controller is that the control stick works kinda funny. It "snaps" to the axes -- try it yourself in the Switch "Calibrate Control Sticks" menu. If you move the control stick up or down, even if you're shaking it horizontally somewhat, it will register as being stuck perfectly along the axis. That's probablly super useful for some platformers but I bet it will be awful for smash bros.
Otherwise I'd prefer this controller due to the button layout and the octagonal gate on the control stick.
I'm making a video to show what I mean, will have that posted up in a bit...