OK, both Nectar and Marks&Spencer accounts will likely store a lot more information about than just your name, so it makes sense to require an email and phone number for added security and protection. For the site like AeroLOPA to ask for BOTH email and phone is a bit excessive.

From personal experience - use available (for free) APIs that check if email was reported as spam - more reliable to prevent bots from signing up. As someone mentioned before, having to provide both phone number and email does not protect you from getting bots to sign up.