If I was starting off afresh I certainly wouldn't do that.
All it takes is for some partnership manager who deals with the GoDaddy rep to get enough pressure put on them about this for the workarounds to become impossible within a few weeks.
And unlike most other things, this being unofficial, there need not even be an announcement with a few weeks to months of transition time. You'll just wake up overnight and it's not working.
Interesting. I didn't realise Apple supported multiple domains. That must have happened after I moved away. I actually went the other way from Apple to Microsoft. I run a Linux laptop and iPhone, and the kids run all Apple kit. I've found the Linux support for MS better than for Apple (Evolution for email and calendar; OneDrive for live home directory sync across devices; and I use Firefox for password synchronisation). I tried to find a way to use iCloud storage for file sync with Linux but found nothing.
I find it cumbersome. I have a custom domain on iCloud and it's terrible for checking the mail from web browser (which I need to do whilst at work).
Not only that. the 2FA requirement is particularly bad. You cannot use 2FA apps (such as authenticator.cc / bitwarden / 1password); the requirement is having an apple device that you have physically signed in on before to be able to allow you to log in. Every single time. Even if you save the cookies.
I have since moved the family emails to icloud mail since we already pay for icloud+ and I get multiple domain support, and aliases.