I can't speak for OP, but for me the problem is that I likely already have normal Chrome windows open when I start a "special" Chrome instance with a private profile and other settings. So now when I see a Chrome window I would like to be sure whether it's my normal user profile or the special profile.
In practice, it's not a problem for me, because the presence or absence of my usual row of extension icons and profile photo is enough of a clue.
But I could see where someone who doesn't normally sign into Chrome, or who doesn't have very many extensions in their normal Chrome profile, could have trouble distinguishing it from their a profile. The windows will tend to look pretty similar.
Exactly. If I need to run a browser in a special configuration, I want to take every precaution to avoid using it for anything but the intended purpose. Since I disable my profile and extensions, I get similar cues.
The problem I see is that not everyone takes the same precautions. And plenty of developers accumulate these sort of tweaks and hacks in their daily driver without realizing or remembering that they've crippled their own security posture.
From a UX perspective, my preference is to make it clear when normal security mechanisms are disabled.
In practice, it's not a problem for me, because the presence or absence of my usual row of extension icons and profile photo is enough of a clue.
But I could see where someone who doesn't normally sign into Chrome, or who doesn't have very many extensions in their normal Chrome profile, could have trouble distinguishing it from their a profile. The windows will tend to look pretty similar.