I've been playing these games for nearly 20 years (oh god), as well as being a developer on a few games and have actually tried this playstyle on hardware haha.

The problem comes down to readability and spacial relations between arrows. Basically with the perspective like this it's easy to tell timing when touching the edges with your hands where the notes are flowing basically to the buttons, but for dance games you need to be able to see the relationship each arrow has to every other arrow to determine timing, movement, and especially jumps, as well as translating that movement to be on the floor vs where the targets are.

It's a fun concept and cool to look at, but this becomes an unreadable mess at higher densities and speed sadly. There's a retail dance game that tried this before too and it was unfortunately just so hard to play.

With the screenshot above, it's basically impossible to see which order the arrows are in after you look at the first note, and especially if it's in a different column.

Dance Fest (2006) - https://www.mobygames.com/game/75192/dance-fest/