An interesting tangent of your BitTorrent analogy is that, for BitTorrent the protocol, an actually legal use case was found later: it is now used to create powerful ad-hoc CDNs for limited use cases with the novel property of gaining bandwidth automatically as more clients show up. The "Linux ISOs" that actually existed were the earliest incarnation of this, driven by non-profit orgs low on cash, but the concept is now in active use also for purely commercial purposes such as downloading large game updates (World of Warcraft, StarCraft 2 etc. have been using this scheme for a long time now) or generally distributing large software packages to a bunch of clients (I've read about at least one company-proprietary project that uses BitTorrent embedded in some kind of software package distribution system to quickly roll out microservice updates in a mesh made up of thousands of servers). This may mean that it's not impossible for some of the crypto protocols to eventually end up being used for actual benefit in some legal way that is not just again financial speculation. However, it will probably be much less world-changing than the crypto enthusiasts expect.