This sums up the significance pretty well...

Bonchie explained over at RedState, Chevron is to blame for a mountain of executive overreach cases and has contributed significantly to the invasive growth of the administrative state:

That’s how you get the ATF banning bump stocks despite there being no actual statutory allowance for such a violation of personal freedom. It’s also how you get the lion’s share of environmental regulations, including literal puddles in backyards being hit with ridiculous, costly EPA enforcement. The federal government has been completely out of control for decades, and the Chevron Doctrine has been at the heart of many of the abuses.