I have mixed feelings about it, even just as a user. There are two reasons people block tracking scripts: 1) privacy, and 2) to stem the deluge of crap that marketing departments dump onto the page, harming performance (both load-time and otherwise) [1].

This basically gives everyone the benefit of #2, even if they don't or can't use an ad blocker. That's pretty cool, in isolation. But of course it also makes it much harder to accomplish #1.

[1] I've seen React-based websites with literally 10x as much JavaScript (by weight) coming in from GTM and other third-party marketing vendors, as the amount powering the actual app functionality. This happens (partly) because every single ad provider has you load their own arbitrary JS bundle onto the page, just so they can measure conversions. This is obscenely inefficient (and frankly, even though it makes things easier to block, in some ways it's potentially a lot more insecure/privacy-invading). People on here complain about frameworks ruining web performance, but in reality GTM is far more responsible (or has been, so far).