Apparently, being out of their mind is one of the characteristics timeshare sales people look for. When it first began, the question after a high pressure timeshare "sales opportunity" was always "who in their right mind would pay $1000 for a week?"
Now, back to todays reality. There are a bunch of people, some in Japan, some in the US, some elsewhere, fully in their right mind, for whom $300K is peanuts. Even if there are 8 3BR Premiers on top of the Waikikian, that's 8*52, or 416 people. It's not that many out of 3 billion.
I unfortunately, am certainly not one of those people. Like you, I couldn't even fathom spending that kind of money for a timeshare. But I do know there are people who have no concept of money, the value of it, how hard some of us have to work for it, or what a 401K is used for. (Sports figures, Paris Hilton, and rock stars come to mind). I can easily see a professional golfer grabbing one to stay at when they are in Hawaii for tournaments, and then using it for vacationing once their career is over. Same would apply for the pro bowl, rock stars, movie stars, etc.
As we all know from watching them drive, the world is full of idiots. Some of them have money too. At least 416.