Why cannot Google robots access scripts?

We have configured our CDN domain that we use for tracking scripts so that it is not available for search engine bots, including Google. Blocking search bots from domains that serve tracking scripts is best practice according to Google and other companies, because otherwise - if we would allow bots to crawl these scripts and it would result in unreliable statistics for our clients.

This has no effect on website using these scripts, it is just a simple way to block bot access. 

How does it look like in Google Search Console?

If you check any website in Google Search Console to verify if it is mobile friendly, Google will also provide info about resources that are blocking themselves from search bots. In example below you can see test results from elcorteingles.es  - and among blocked scripts there is googleadservices.com as well: