As the maintainer of certbot for Debian, I promise you that there's no intention of deprecating the certbot packages that exist in the archive. The EFF fully supports this decision and has promised to continue to assist. Their recommendation for snaps is meant to target new and inexperienced users who may not understand why they are not getting the latest software when they see it was updated "on the website".
If any of you have concerns specifically about certbot on Debian, please feel free to contact me directly at my username @debian.org.