I don't get the "this is expensive" argument. For a professional photographer who buys this camera and throws it into the dustbin after 150,000 exposures, the cost would be $0.05 per click. A typical event would for me equal a maximum of 2,000 clicks, which would then sum up to a camera cost of $100. Lens cost would be much lower, but let's say that other "hardware" costs are $100 too, and we are up to the grand sum of $200. If my income from photography can't cover that level of cost, I should look for other work (which I have, so I'm not a full time photographer anymore). For smaller jobs that require fewer exposure, portraiture for example, the mathematics look even more favourable.
Backup is of course an issue, but if this proves to be a reliable camera, a Leica T would be a great backup, although a separate WA lens would be needed to compensate for the crop factor.
Some claim that 24MP isn't sufficient, and that's fair enough, but I also think it's fair to say that users of the most common DSLR brand in the world, the one called Canon, haven't had access even to 24MP until very recently. Still, several of them have been able to make a living from their somewhat inferior cameras