mswcpt, in an Apple discussion thread back in 2013:1
Like the other other Apple customers here, we don’t want to have 2, 3, 10 or 7 email addresses. We want ONE. Because we had (now in hindsight directly caused this problem) by using a NON-APPLE email intially [sic] as the ID and then an @icloud address for the icloud account and email, we are the ones NOT in a position to get rid of the email associated with the ID and move it to the icloud email address. There are fortunate people out there who have set-up new accounts, devices from scratch who were not Apple customers before that have been able to from the very beginning have their icloud address as their Apple ID, and therefore ONE account.
This means that us poor sods have to go through the inconvenince [sic] and frankly seamingly [sic] unecessary [sic] pain to create digital clutter in our lives and be forced to open some unused email account simply to use it as an Apple ID. What an utterly perposterous [sic] and cumbersome system.
I think it is ridiculous.
Yes, it’s very ridiculous. When I am at https://appleid.apple.com/account/manage and I try to change my Apple ID to my iCloud email, it spins endlessly with this console error:
Potentially unhandled rejection  ReferenceError: logError is not defined
If I use a different iCloud email address, I get this error:
Your Apple ID cannot end in @icloud.com. Choose a different email address.
I’m forced to have a primary non-iCloud email as my Apple ID and then have my @icloud.com email as an alias. Here’s what I see when I click on the
? at the “Reachable At” section of the page:
This is an alias of your Apple ID email address.
Give me a break.
Hopefully you can arrive at the person’s intent through all the misspelled words. ↩︎