Note that this is not a new service, but the discount percentage has been increased:

“Previously, we gave a 2% discount, which was probably only significant for high volume senders. 10% makes it significant for everybody.”

However, I'm still not doing it – too much hassle. Instead, I just have 1Password create unique passwords for each service I use and change the passwords once in a while.

That said: I'm a satisfied MailChimp customer and I really appreciate that they continue to improve their service.