I think the real significance of this ruling has nothing to do with guns-- the court affirmed that states cannot simply carve out exceptions to Constitutional rights. Want to "fix" or remove the Second Amendment? There are procedures in place to do so. Overriding the Constitution with additional laws/rules/regulations is dangerous.
As I've said before, if you want to strip a populace of its rights and freedoms, you start by working on things that are unpopular. Lots of people are too eager to cheer for this attempt to undermine the Constitution, because the Second Amendment is involved. But this kind of thinking assumes that the government will stop there, instead of going ahead and weakening the Fourth Amendment. Or the First.
Authoritarians believe two things: that the populace doesn't need much freedom or many rights, and that they are the ones who know how to run things the best. They also think that they are the ones who will be in charge when the smoke clears, but that is almost never the case throughout history. So when they weaken the Constitution, they think they're making it easier for themselves to rule, but they're really just making it easier for the real monster, whose first action is usually to get rid of the people who made their ascension possible.