Again, the only flaw I see for exclusive game time card are the world transfer service, since from what I see, there's no form of cash shop or additional services in FFXI. It does become a major flaw in XIV, not just other cash shop & additional services, but also those XIV players who has legacy billing. And yes, I am one of those XIV legacy players who suffers from this.
But as for XI, at least this game time card might be a good solution, given there's never be a discounted billing prices like what legacy players in XIV had. And according to some friends who's not a legacy player, prices on those game time card are actually quite worth it and cost slightly less than what you pay directly.
Unless... you like to hop between server really alot tho... lol