The advantages over lithium-ion are not clear to me. Is it just cost?
So we have a battery that has better charge cycle life expectancy and uses a more readily available "cheaper" resource.
Providing massive, (relatively) cheap battery backup to these intermittent power sources could allow Germany to accelerate the transition away from coal, which they've been forced to use more of due to decommissioning nuclear plants. If the power companies are willing to invest heavily in infrastructure for renewables, it bodes well for them investing further in batteries to improve grid stability and prices.
[1] http://www.spiegel.de/international/germany/electrical-resis...
Cheap batteries would allow every country to move to renewables.