not to mention i18n is built already (not sure if @misha did a pull request, but it s question of time.) not to mention @misha already built a feature that auto-detects country then recalculates $numbers to local currency using yahoo-provided exchange rates. this works locally, and can be merged into steemit.com repo.
but still forking makes sense - different token distribution, another (not dollar) currency binding (probably this also won't make sense for you. :) ), ability to tweak logic of tokens flow (it s probable that steemit solutions are biased culturally - like all solutions people make daily), different copyright policies - ton of reasons possible.
The proposed solution of having a different chain still doesnt solve all of this. Additionally steem itself is capableof creating steembacked(enter fiat here).
Want to be paid in steembacked gold instead? Its possible!