There are two ways emails about updates can be sent:

1. You go to the emails tab, write an email, and pick the list of people who you’re sending it to. This list is never populated by people who have downloaded a free game. You can only directly email people who have paid for your game, people you have imported from kickstarter/indiegogo/etc., or people who have claimed access to your game via a download key
2. You publish a devlog and your account’s followers will get a digest email (if they have it enabled) sent to their account with the update

Just to reiterate, downloading a game has nothing to do with email eligibility.

Hope that helps