I've checked out some of these survival seed websites. Their point is that most of the seeds that you buy at the seed store are hybrid varieties, and supposedly produce sterile seeds. So according to them, if you buy regular seeds, you will have food for the first year, and then starve. I don't think this is necessarily true. Not all hybrid seeds are sterile as far as I know. I have grown hybrid melons cantelopes, for example, and used the seeds from them to grow more the next year. But I'm sure that some hybrids do produce sterile seeds.
Most of these survival seed packages are being sold by pretty extreme survivalist types. I think the idea of being able to hide them from confiscation is so that when the antichrist appears, and requires you get tatooed with a 666 to buy food, you'll be able to avoid doing that and grow your own. The theory being that the antichrist's minions will be going around confiscating your seeds.
I think these seed packages are a bit overpriced though. If you do a little work, you can find non-hybrid seeds on your own, and package them up using a Food Saver or something similar. As for the antichrist's minions, I hope their heads are highly resistant to a 7.62x39, because that is what they will be faced with if they want my seeds.