Just tried this out using a typical temporary email address (temp-mail.org) and a VPN (AirVPN).
I was only asked to confirm my e-mail address within 3 days, never for a phone address or any banking details.
Judging by the first post you’ve linked to, it’s only necessary for paid accounts or free trials.
The person in the second post is trying to register via GitHub / Google, well… sucks for them.