I can't see what Haiku offers that modern OS X doesn't.
That's not really the point. Haiku's intent is to keep BeOS alive. At the time (over 10 years ago), BeOS was the epitome of a modern OS. The pickings were slimmer back then.
Of course, it took almost that long to make Haiku happen, and the OS world has changed significantly since then.
For a "modern OS" BeOS lacked a lot. Shoddy hardware support at best, a terrible network stack, did it have a printing subsystem? I know they wanted to rebuild the networking stack I don't remember print being good. Internationalization was non-existant.
It was an RTOS with a UI on it, sexy and clean, I'm not a hater but a long long long way from NextStep or OSX.
Replace shoddy with limited and I could agree with that. BeOS died very young.
Pretty much all those points could be made at the inception of any OS. OS X had a nice jump on that because it was NextStep and had been developed for well over a decade.
To be fair, much of the needed work was accomplished in the Dan0 development release that was leaked near BeOS's demise. This included the BONE network stack and some 3D support. Everything about Dan0 was, of course, very much development code, but it was definitely a marked improvement over R5. Haiku was able to use some of the Dan0 high level kits in place until rewrites could be made.
Clearly the Apple/Be Inc. issues were sorted out to Apple's benefit, but it's still neat to see what could have been. OS X had its own issues in its widely released beta, after all. ;)
That's not really the point. Haiku's intent is to keep BeOS alive. At the time (over 10 years ago), BeOS was the epitome of a modern OS. The pickings were slimmer back then.
Of course, it took almost that long to make Haiku happen, and the OS world has changed significantly since then.