I tried them once just to see, did nothing, just molded in the cup I had them in. I was concerned that they might, so didn't put them into a tank. I believe someone else on here had the same experience.
I know they're cheap, but they don't seem to be worth it. I didn't mail them back for a refund, it was not worth the effort, I'd say that's probably how they can make that claim.
Also, water lilies are not aquatic. Back in the 90's when the betta peace-lily craze hit, it was always really important to NOT put the lilies all the way into the water, only the roots, and even then half the time they'd get root rot and die.
Here's a much better option:
I don't know for certain if these are aquarium-specific, as I haven't bought the package before, but if you contact the company, they can tell you. This company does come highly recommended though. :) They've also got some really beautiful plants that I haven't seen other places. :)