Purely from a business perspective isn't it smarter to use other people's money for such risky projects? Musk certainly didn't become a billionaire by gambling!
IIRC Musk wants nothing to do with Hyperloop, and the boring company appears to be the marketing name they gave to a purchase of a pretty standard tunnel boring machine to dig a pretty standard, good old fashined tunnel at SpaceX's.
That's it. The rest is marketing.
Comparing with the level of investment in Tesla and SpaceX, both with regards to personal time and money poured in, it's pretty easy to notice which projects are handled seriously and what projects amount to marketing.