Really good point and I agree. This was intriguing at first glance because who doesn't want less JS on their site?! Of course! However, missing out on other events being tracked, advanced demographic information(?), and what else?? That's a huge miss - especially if you work with Google Ads and have your Analytics linked. Your ad campaigns won't be as effective and could potentially cost more money to save someone an unknown amount of loading time.
This is pretty creative though.