I don't see why they mean anything to any fan unless the show is about to be cancelled which clearly isn't the case with AEW. Obviously, they mean something from a business perspective but they care more about certain demographics than the overall rating and I'm pretty sure AEW is doing fine there. The numbers also aren't accurate at all as far as how many people are actually watching.
1. The numbers are as accurate as you're going to get when it comes to cable and network TV. And as long as Nielsen is the best game in town and the broadcaster and the advertiser both listen to them, they're going to matter.
2. We honestly don't know if they're "Doing fine" yet. I fully expect them to get a deal done, probably with WBD, but I'm skeptical how lucrative it actually is for them. NBC (USA) has social media accounts openly mocking Tony and is seemingly content with Smackdown's rights. FOX is apparently out of the wrestling game after they weren't happy with Smackdown.
Seems like WBD is the obvious destination for them, which begs the question of "What's the hold up?" Seems to me the obvious answer is that WBD isn't making any decision until they find out how much money they're going to have to pay the NBA. And if that costs a lot, that probably cuts into the AEW fund.
3. Even if demo ratings are doing well, it's not necessarily great for advertisers. It's been pretty well known for awhile that wrestling fans have a stigma of being poor in the advertising industry. To the point that Meltzer said a few years ago that's why the NHL can pull in way less viewers and still bumps AEW.
AEW doesn't really help themselves in that regard by constantly putting shit on TV that advertisers cringe at. NWA found out the hard way very quickly with this one. Which is honestly why I think AEW would be better off on streaming. The rules aren't nearly as strict for the content they want to provide.
tl;dr on "How does this affect the fan?" - Tony's been throwing millions at talent under the auspices of an incoming big TV deal... If he doesn't get that big TV deal, does Shad keep flushing tens of millions to finance Tony's fantasies?