Question is: is it convenient enough?
There is not enough information out there yet to say. I think a lot will depend on how well the client is written and how easy the payment procedure is.
Another question is whether they will insist on people using their client or open up the format for inclusion in third party media players etc.
When speaking of torrents, why download the "paywalled" version if the free one is right next to it?
I know I would opt for a paid version; albeit from a different channel. But I just don't see the current bunch of torrent users picking the paywalled version over a pirated. They're often (with exceptions naturally) people who don't care about the ethics and morality concerning intellectual property...
I don't think these bundles would be very popular on The Pirate Bay, but they could be distributed via the artist's own site or via a store/portal/search engine that only contains these bundles etc. Studies have shown that a lot of the big media consumers both pay and pirate. Of course there are people who will never pay for anything, but there are also a lot of people who will pay in the right circumstances.
In fact, some of them will go to great lengths defending their position by claiming it's really all just "data" and "information" which should be "free" to begin with, so the evil big corporations really should burn in hell for wanting money for it in the first place ... ish.
A lot of people don't realize how much effort it takes to create something of decent quality, because they've never tried it themselves. As for opposing the megacorps, that sounds like an excuse to me. If you're really serious about undermining the power of the MPAA/RIAA, don't pirate their stuff, but buy from indies instead.
I welcome any initiative which has the potential to channel money to the artists. But this? I just don't see it.
I have no idea whether it will be successful. It does have some advantages: The peer-to-peer nature of BitTorrent means artists without a big budget can get their works distributed without having to pay for a lot of bandwidth. And if the unlocking works as I expect - buying a decryption key from a server - the reward for buying the content is immediately available, since the files are already on your harddisk.