Jake,
A catamaran roll tack is by far the fastest way through a tack, but we all cannot perform this maneuver perfectly each and every time.
Once in a while you might slam into a wave about half way through the turn that stops the boat while it is directly into the wind.
That is when you have to quickly scull the boat to close hauled and get going again.
I really don't recall that as being against the rules.

But to scull your way through every tack would be very, very slow indeed. If you blow most tacks, it may be the only way to go.
As Mary said, to skull while on a close hauled course has always been illegal.
Rick