no you should read it as: the blockchain is a central point, so there must be a fix for the problem. If/when there is such a problem in the future. Here in GS people/devs can just ignore the #data_portability (due to prio, ... or whatever) and thus binding the users still to their original instance. if the blockchain would ever be too large: it'd deter new users (since you have to download all first). It'd be a central problem. Also for non-new-users, thus MUST be addressed