What's the significance of attribution of exploit source?
You claim this based on what? Kaspersky has recently found what they claim is (another) massively complex US malware in the wild.
> What's the significance of attribution of exploit source?
As in my example above, people always look for the source of an exploit and claim various actors created them. This creates certain reputations for these actors, just as in the claim from Kaspersky above (which may or may not itself be true - Kaspersky is a private company, but it is also known to work with the Russian government, which is clearly antagonistic to the US).
Noone can bullsht too often; attribution for hacks/tools as disinfo has limited utility value. And, again, attributing brain injuries to REW's as disinfo wouldn't help and they know that.
I still don't believe the US would decide to lie about this matter.