The thing that's nice about the limited-time double _______ event conceptually is that there's a psychological tug in play. Even if, for instance, most people wouldn't NEED IS enough to justify a Double IS Weekend, or it wouldn't help them greatly with long term goals, a lot of people would go out and get IS anyway because it was a Thing That Is Going On, and just having a whole bunch of people in one place doing something other than standing around is fun enough to justify whatever minor inconvenience would come of its implementation.

Having every weekend double something would be pretty fun and would be nice to look forward to.