No. Most email clients (including Gmail and Outlook) cannot play embedded videos.
A common workaround is embedding an image or a GIF of the video in your email. Then, hyperlink the image to your video hosted on another website (e.g. YouTube).
To hyperlink an embedded image or GIF:
Click the image icon to upload a picture (e.g. a screenshot from your video)
Insert the image
Highlight the image
Click the link icon
Enter the URL of the video
Note that you have to convert any MP4 files to a GIF before trying to upload it in the Pitches composer above.
If you're going with a static JPG image instead of a GIF, usually you’ll want the image to be at least 600px or wider.