TLDR: This is digital identity obfuscation for web privacy. Advertising and marketing networks have gotten exceptionally good at tracking people across the web. For example, if you have a Google account, you can go into your Settings for Google Ads to see your Age/Gender inference.[1]
I can’t believe people really care that much about seeing ads for pet food after Googling for the vet that they would let something like this run constantly in the background. Absolutely unfathomable to me.