Only downside of Yaas Queen: BD3 is "only" +2 with her.
Other ender is more plus but out of F4 range (but it is still a good option for other follow ups as you have more respect). So against 6F D1 she might be trouble. Against 7F D1 the trade is Cassie's favor.
But in the corner it is even better as other restand is more plus and up close. So good trade off.
Theory fighting: I think against Scorpion also Yaas Queen might be the better variation.
I can use knee capping 2-4 times / matches and the main purpose to bait teleport by buffering it however I risk myself with that few knee capping to be punished anyway.
For teleport bait the straight shot cancel can be also effective or I do not know need to test it.
Other than that Scorpion can get away with a breakaway after a risky move which Yaas Queen would not allow and it is a thing. Especially Searing Rage who can not use his def meter for everything else (no wake up if mostly restand).
Reborn can use his def meter but he will teleport even more so knee capping is not better either.
I will practice her Bnbs and give her a go against Scorpion too.
I heard 1 frame link in Bnb wtf? Sonicfox also dropped it several times it can not be "good".
I am interested in your experience as well.
EDIT after few minutes practice: B24 | F41 | F2 | 111 xxDB4 AMP, B24xxBD3 or DASH, 111xxBD3 is not that difficult for the okayish damage (around 22%).
"I know Kung-Fu".
She needs new anti air, J3, B13 mid screen combos but fortunately it is also pretty good damage for 1 bar (I use AMP straight gun ender) just a bit short and boring lol. And in that case you do not get restand. For restand you get meterless less damage - it can be also good as saving bar for reset position is never bad.
I do not really like that low damage output but yes it is unbreakable and guaranteed. It looks like Cassie... everything is stable nothing crazy lol. I will check it in action today.
In the corner she has pretty good damage so with Yaas Queen the situation is turned - she is more effective in corner. I like that way though.
But with 34 involved the opponent can break away so likely they will do if they can not send their def meter elsewhere.