Passwords are mandatory (and always have been) but you can enable
autologin in gnome-control-center. This allows you to log on without
typing your password.
Problem is, unless you have a LUKS password equal to your user account
password, you'll just get a modal dialog when you log in prompting you
to unlock gnome-keyring. So it's never really worked.
So, as I understand that, enforcing per-user encryption is not going to prevent anybody from having automatic login? User account has to have password anyway and having per-user based encryption (4.b.) would mean that LUKS password would be always equal to user password.
The only case I think disabling encryption might make sense is the absence of AES-NI instructions. However, it seems like they are missing only in older low-end or ancient CPUs [0] and even without those instructions, actual encryption/decryption speed seems to be around 200 MB/s (sure, CPU load spikes whenever you write/read). I don't expect too many systems with SSD or even (SSD) NVMe drives and CPU without AES-NI to be around.
Disclaimer: I didn't actually do any benchmark, just googled a little. I am only mentioning it might be worth finding out if it isn't too much of hassle (and I don't know how difficult this is going to be in g-i-s/Anaconda) to add logic for detecting instructions presence and not encrypting in cases where they're missing. I can try to get some numbers if there is need/interest for them.
Please, Franta, let's not spoil the traditions of Linux being a free (as in speech) system where everybody is
welcome to do as they want.