Makes as much sense as switching to OS X. The Mac OS is not Linux.
If you're developing for Linux, or using something like GHC where the OS X version is a least-favorite stepchild, or if you need package management as capable as APT or the FreeBSD Ports Collection – then if you aren't running Linux as your desktop OS, you're most likely running it in a VM, regardless of whether your host OS is OS X or Windows. In fact the author explicitly says he's doing as much.
So "somewhat but not quite like Linux" isn't something the author would strictly need to look for in his host OS. Intead he can take other factors into account, such as reliability, performance, available applications, and hardware choice, quality, and cost.
Sure, but it's much closer than Windows. OS X is a Unix and things written for Linux will often compile on OS X without significant hassles. Windows has some optional layers to do this but it's not the same as running a Unix through and through.
The VM route is an appealing one though and one I use myself from OS X. From what I've seen virtualizing Linux under OS X is a more seamless and pleasant experience than on Windows but perhaps things have come along there since I last looked.
But, still no binary packages.