It was something that was taking a long time to arrive, although, as you can see, one of the novelties that the new update of one of the most used email platforms in the world will present, such as gmail, is precisely about the possibility that now all power users will have play a video via streaming without having to download it previously to our hard drive.
As a detail, tell you that this new update of Gmail will be available to all users through a deployment through which, little by little, everyone will have access to it. The dates that are shuffled so that everyone can access this functionality go from yesterday, for the first to have access to this new version, until the end of this month of March, date in the world should be able to watch videos without having to download them.
It will no longer be necessary to download the videos that come to you via Gmail to be able to watch them.
Another detail to take into account is that we are not talking about an update for the applications of the different operating systems, but only will affect desktop version, one of the most used, especially at the business level and that, now, will save a lot of space on the hard disk of our computers.
Going a little deeper, as has been commented from Google, this new video preview system makes use of the same video transmission infrastructure that all YouTube users have had for a long time, which, in turn, is also used on other platforms such as Google Drive or other streaming applications created by the company. On the negative side, note for example that Google will continue to keep the limitation of attachments less than 50 MB, so the videos we send will be small and of low quality, as before.
Further information: Google