Given I have a milk allergy, I guess it would partly depend if the whey triggers it or not. I think it's the casein that's the issue, so a bovine casein protein used to make certain vegan cheeses would probably be off-limits, but I haven't tried pure whey.
Guess I'd be open to trying it, but given the price, it's not of interest currently - it would need to get below oat/soy milk for me to think about it. Secondary products using this type of tech would be cool if it could become cheaper than current alternatives.