Well, yes, this is being used in corporate environments but the end user and the system admin aren't on the same page necessarily. Domain blocking doesn't make much sense in my opinion and should be a thing of the past. You already lack admin rights so what is a block on e.g. mullvad.net actually doing other than stopping someone from reading their blog? They can't install the VPN software.

Defense in layers makes sense, but domain blocking was never a "layer" if a hostile actor can just buy a new domain that's not on your blocklist.

I think it'd be good if ECH became more widespread so that we can get away from these antiquated control techniques that just result in frustration with no security benefits.