That's why it was phrased as a question. Take it easy, buddy... How is it with the size? Universal?
All good. I just have a latent half-knowledge allergy. Of course it's not universal, since it's made of metal and very, very slim. But it's available for almost every series. Luckily, the Apple devices have a pretty long lifespan and rarely change their shape within the series (iPad, iPad Air, iPad Pro, etc.) across generations. For just any Android tablet that stops receiving updates after six months, I definitely wouldn't spend the money. That's why this thing doesn't exist for Android either.
If I have to get up to go to the wall where that thing is hanging, I can just as well go to the table where that thing is currently lying.
That's the case with all permanently mounted displays. They are usually in central locations where you often pass by. And above all, they are not intended for constant use but rather for central functions. However, if you use a tablet for this purpose "like a tablet," it basically never lies where you currently need it or is empty. With small children in the house, it usually ends up in some drawer. Then you might as well forget about it. If I want to have the functions always nearby, I take my smartphone.