Apple literally built a feature that requires addition to PSL to support a usecase that was addressed multiple times in the PrivacyCG meetings. How is this entitlement, they are following the Apple requirements.
If you're at the point you're spending money on ads and need to track them, you can spend $10 on a domain name? Lots of these platforms also give away free domain names.
It's not about whether or not it's foolish - the point is buying and setting up a subdomain, handing SEO, etc. is often more complex than some small business owners want to deal with.