YSK: You don't need Gmail to create a Google account
Why YSK: A Google account is not the same as a Gmail account, and you don't need to create a new Gmail email account to have a Google account.
I've spoken to many different people who equate a Google account to a Gmail account. This is not the case. Unfortunately, this leads to many new Gmail accounts being created, solely because they think that they need to have a Gmail in order to access other Google services.
Here's the gist:
A Google account gives you access to Google services like Sheets, Docs, Calendar, Drive, Photos, Gmail, YouTube, etc.
A Gmail account is an email service account with Google. When you create a Gmail, you also create a Google account by default.
However, the reverse is not true. If you create a Google account (with a non-Gmail email address), it does not automatically give you a Gmail account.
If you already have an email account with another provider, you can use that as your Google account.
Why YSK: Using these instead of made-up domain names reduces the chance of confusing readers, eliminates the possibility of phishing attacks, and avoids sending unwanted traffic to made-up domains if they happen to belong to someone.
You're making a new account either way. Whether you login with a gmail or other email address makes no difference to it being a Google account. Making a gmail you ALSO get another email, which you can promptly ignore until some possible point in the future where it may be useful.
I suppose "harm" can be subjective in this context, and there are already some good replies here.
One more thing to add to the list that I'd consider harmful in creating a Gmail account is all of the privacy issues that come with having a Gmail account.
Out of respect for my recipients and myself, I wouldn't want all of our emails being read.
We can go down the rabbit hole of "Email is inherently insecure anyways," but that's a separate discussion.
I wouldn't know. My Google account is older than YouTube, and GMail was just getting out of the beta stage. Smartphones didn't exist yet, nor did all these modern fancy apps.
So the signup process was totally different back then. And when they acquired YouTube, that meant I automatically had a YouTube account, but oddly enough I had to use a different username than my Google account, to avoid conflicts as they merged.
I only use Google services on the devices I leave at home, my mobile devices will never see the likes of Google though. They don't have any business tracking all my activity, so as far as their systems know, I haven't left home in over 3 years LOL!
Except your google devices at home see your local wifi and the same degoogled devices are logged on multiple wifi netowkrs throughout each day so they still track you.
So is this why I’m able to receive new emails from the Google Group I joined with my non-Gmail account, but not actually access the Google group to see past messages to the group?
Sounds like it. It happens with other Google services too. Someone could share a GDoc to your non-Gmail email, but if that non-Gmail email isn't a Google account, then you won't be able to access the doc/comments/whatever else (depending on the doc permissions, of course).
It's totally possible to do without the suite! With my free Gmail account and my domain registered through cloudflare, I have a custom email address for just the cost of the domain. I have the custom email set as an alias in Gmail, and Cloudflare does routing.