"I doubt the businesses would care. They may be getting nothing but noise but they'd still package it as good data and sell it on to their customers who I seriously doubt would know any better."
The businesses would realize something is fishy after they run performance analytics on their illicit-data-driven ad campaigns, at which point their software informs them there is zero relationship between their ad-targeting and their customer conversion rates.
But even if THAT weren't true, which it is, you're still missing the main point, which is that your personal information has been poison-pilled like an exploding ink pack in a compromised ATM machine. Not only does this make your information useless to advertisers, it makes it useless to anyone who might commit fraud, extortion, intimidation, or any other act involving you and your data.