if the idea is to protect users so that you don't end up clicking on https://news.ycombinator.com.myhackerdomain.com , you then open the attack of a platform where they offer custom subdomains, and you have
and then
https://fake-original.blogger.com
if I make them look the same, and the address will hide the subdomain, it looks like a step backwards in securing the web
now, imagine the actual platform has a payment section, and I create a fake subdomain that looks pretty similar, email you, boom, I get your cc info because I tricked you into entering new cc info (assuming your scenario of someone being distracted)