VPC adds an extra layer of security through isolation, but it was not our main reason to migrate. Since we are moving terabytes of data between our servers every month, we expect the network connectivity to be a bit better. Besides, VPC gives a few more configurable options that are quite handy.
Bitcoin… it might evolve into something, or it might crash. It's a highly volatile pseudocurrency. Although we wish it nothing but success, we are still discussing to which extent we should use it.