For example, suppose you go to https://som.example/ which is the web site for "Somex Ample" products. You don't trust "mere" DV certificates for som.example, which you believe may be purchased by bad guys, but you're comfortable because "Somex" has purchased an expensive EV certificate for "Somex Ample" of Springfield.

You fill out a form on the secure web page, and hit submit. But, unlike you, your web browser intentionally has no idea who "Somex Ample" are and no interest in whether they spent a lot of money on their certificate. When the server it reaches has a boring DV certificate for som.example that's fine, the browser compares this name to the name in the HTTPS URL and it matches exactly so that's fine. The browser sends your form data to this server, gets back a 30x redirect and then (maybe after some more bounces) gets a fresh web page to show you. This page might come with one of those shiny EV certificates you like, or it might not. Either way, that form data you were careful to only fill out on the "safe" EV page, went to a server without an EV certificate.

So, getting rid of the separate UI indication for EV was largely reflecting a reality that already existed. The DNS name is correct because the browser always verifies that matches at every step, but if you're relying on something else it's on you.