As in, "Why not use the Mac OS X native tool?" That's a fair question. I don't have a particularly interesting answer for it though.

When I first purchased and flashed my N800, I used the flasher Nokia provided right off the N800 support page on their website. I don't think I was even aware of flashers for non-Windows platforms at that time, and I didn't have a need to search an alternative out, as one of the machines on my desk at work was a Windows box.

Later, when I moved everything from that Windows box into a virtual machine, I installed the Nokia flasher there too. It had worked well for me in the past, it seemed the most official, and the available documentation for alternatives solutions was in an even worse state than it is now.

I've never had any need or desire to use any of the advanced options available in the command line flashers, so I haven't felt the need to replace what has worked well.