So for normal (non-admin) users there is no way to opt-in to this. I can't understand that.

I don't think anyone would have a problem if this was a simple opt-in system like downloading unofficial apk's on android. Only a select few would be opting in, and those are not the core audience that Google is pretending to be security conscious about.

Giving no ability to switch on this ability for a normal user makes Google lose face with the general tech community. I don't understand the reasons behind this.