Admin email for new user goes to site_mail address

When register accounts is set to "Visitors, but administrator approval is required", the email to the administrator goes to the email address set as the system email address. There are a few problems with this (in decreasing order of importance):

1. The primary purpose of the site email address is as the "from" field of outgoing emails. This is often a "black hole" email address. I can't do that if it's got user registration notification emails going there.

2. Nothing on the site information configuration page says that emails will be sent to that email address, thus making me think it's ok (encouraging me, even) to set this as an email sink.

3. The user management page says "administrator approval is required", which suggests the email goes to the email address of the administrator user, not the site email address. I had to hunt around for a while to figure out why my user registration emails weren't going where I expected, and instead were going somewhere that I'd explicitly configured as an email sink.

I see that this issue is flagged for attention in D8. However, I think it's important enough to be addressed in D7 for obvious reasons. Having the emails go to the admin user email address would be far better than what's there at the moment, but even that is problematic, since admin isn't necessarily responsible for approving new users.

If the actual functionality can't be fixed, then at least the field labels/descriptions should be fixed to make it clear what is going on.