A necessity in many cuisines, from Ethiopian to Indian/Pakistani. It is also shelf-stable, because the milk solids (which spoil) are removed. It can take a higher cooking temperature without smoking the way regular butter does, again due to the removal of milk solids.
We have a huge Ethiopian/Eritrean community in the San Francisco Bay Area. You can tell the ones who do the "healthy" cooking with olive oil instead of the proper niter kibbeh, spiced ghee. It simply does not taste as good - the flavor profile is 'flatter', for lack of a better word.