> But so much of that tracking isn't really necessary.
The problem with Google Analytics and tracking is it's hard to tell what the motive is for putting it onto your site from the visitor's POV.
Not everyone who uses GA is using it for evil purposes.
They use it because GA makes it easy to gain useful business metrics, such as 100 people visited this page, 30 people filled out the account form, 5 people completed the checkout. Now you have a way to measure how good or bad your checkout flow is working and implementing this took almost no work at all. Rigging up your own DB model and tracking this stuff locally is a huge burden (especially if you account for bot traffic).
GA is also really useful to track referring URLs (with UTMs) because if you use these links from Youtube videos or blog posts, suddenly you can see exactly which posts are doing well. And "doing well" isn't just being more profitable if you're selling something. It helps you know what to write about or make videos on because this is what people want.
At the very least it's also good for just answering "am I growing?" where you look at unique visitors on a monthly basis and hope to see your chart moving up per month.
I just see it as a pragmatic tool to help you measure things. It's unfortunate it can also be used in other more malicious ways.