BleepingComputer.com: distinction between google account and gmail confusing

The google services page tells that a google account does not automatically give the account holder a gmail account, yet the google account registration form plainly shows a 'choose username' field with a "@gmail.com". This makes me confused. Later, in the page's services description, the visitor is told that if he signs up for a gmail account, his first username becomes his alternate gmail account. I do not understand. If someone understands this and can explain, please explain.

One registers for a google account and then later, when signed in to the google account, one can also register for a gmail account. What is the meaning of these two usernames, or is this still only ONE username? Two gmails now after making only one google account and then one gmail account? Someone straighten this. Maybe the google account registration form only mistakenly shows the "@gmail.com"?

How about that whatever they say on the Google services page is baloney. I have a GMail account but I never started it and I don't really use it. But Google wants to use GMail as a default addy for anything they might send like from Youtube, Adsense etc. The one thing you can do is sync it up with your regular email account so you get all your email in your GMail account and you can use either account. But I can assure you that Google assigns a GMail account to anyone who opens a Google account.

Quote

This may now be the case -
I set up a Gmail account 3 or 4 years ago, just for a spare access account, and then I needed to give another account for them to check I existed.
This was so they could also send details that the account had been set up.

If you gave another email account as "contact account" they know you exist, and will set up a new Gmail automatically now.

Thank You -