I have received the same offer; same terms as noted above. I'll also kick in my stats for the sake of reverse engineering:

I was silver for a few years, but lost it in 2019. I dropped my Delta Gold Amex at the same time, but have a non-Delta Gold Amex.
I had a few trips last year on Delta, including one in PS to SCL. Presently have one trip booked to ATL later in the summer. That's it.

Rather surprised to find myself a target of a promotion -- curious what drove it.