They just remove one cat-specific allergen from the cat. There are plenty of others. If, for instance, you're allergic to dogs and dogs today then you'll be allergic to these cats as well.

Furthermore they don't intend to deliver for 3 years. It sounds to me like they are promising something that they haven't quite figured out how to do yet, but think they will. Maybe it will work, maybe there will be glitches, maybe they'll run out of money and never deliver.

Cheers,
Ben