Do you mean combining the eye tracking with using a lenticular screen? What would do you think the use cases would/could be?
1. Each eye sees the object from a different angle.
2. Both eyes see the object from a different angle when the object is moved relative to your head.
The 3DS does only #1. TFA does only #2. Presumably if you did both, you could get a much stronger effect.
I think the New 3DS had the hardware to do both in theory, but it probably would have made development and backwards compatibility overly complicated!