This makes no sense. Safelists (new or old versions) have always been credit based, from the get go.
Safelist and Mailer is the very SAME thing anyway. I've owned them since year 2000, or before, and mostly known for that realm.
As for email addresses - Mine always ask for one email address from the start, so it is not nothing new at all.
Those who ask for a contact email (new or old), they really want to email you separate from the list mail (like admin updates or a push on something) and/or they sell "solo" ads (incorrect definition) to send an email to the contact emails.
Around 2009 they started to be more common to also be called mailers. In which I called and bought domain names for both words, as it is the SAME thing.
But then around 2010, a script started to be oversold to death and they called it viral mailer.
- They are an incorrect description as it is not viral.
Anyway, old safelists have always asked for one or two, and have always been credit based.