It's not viable to use it to visit the galactic center during a lifetime, but it still flies, if I understand that correctly?

Theoretically it works, yes, though not nearly as well as initially thought. The engineering and the required materials, however, are still questionable and way beyond our current understanding of physics and material science.

It's a similar story for solar sails, unfortunately, though progress is being made in that area. Personally, I think that's the only realistic way of interstellar travel given our current knowledge of physics and engineering.