The promotional e-mail sent out by CCP says that the account can not only be used for training skills on two pilots at once (impossible with two pilots on the same account) but also for "extra firepower on missions" or "an extra hauler for miners." So, legitimized multi-boxing it is, then. Cool. EVE just has to be different in every way it can, doesn't it? It's a compulsion.
The offer's available until October 10th, so you've got a while to mull it over.