Hold on, lemme get the script...
Ahem
The 3DS family of systems continue to sell well as the Switch currently isn't at a price point friendly to younger children and lower income families. It only makes sense to continue supporting a platform that has dozens of millions of active users and a large possibly consumer base, especially when doing it with relatively low-impact remakes/compilations.
While I agree with you that WarioWare could have shown off the Joy-Cons well, the series isn't necessarily THAT popular, and is also relatively crass, so I can understand why they'd choose a more neutral, non-IP based tech demo game to show them off. Also you seem to forget that Touched and Twisted, on two different generations, came out within months of each other. There's always a chance they're working on one, and Gold is just testing the waters to see if there's any interest.