For those looking for a self-hosted solution which doesn’t require a monthly payment, there’s https://sendy.co/. I never tried it, just remembered it exists.

Mail Layer does seems to have a bit more features, so pick your tradeoff.

As for feedback on the page, the mobile design isn’t exactly broken but it does have a number of problems. It’s so squished at the top it reads:

  Mail
    Documentation
  Layer

Playing the video, its right side is entirely cut off. The “Frequently Asked Questions” title overlaps the questions themselves.