First of the amount of email clients that actual support embedded video's are very limited. So to create a video we need to make a solution for either all email clients or find a smart solution that will show different options depending on the email client you are working on. For instance if we look at Gmail which accounted for 36.5% of email opens globally in 2021, they do not support embedded videos in their phone or online clients. Apple on the other hands support embedded videos.
Popularity of Gmail is partially of course because it getting shipped standard with Android. Apple mail is doing well for the same reason. Of course from a business point of view we will need to take Outlook in account. Even though its losing market share it still one of the more important email clients in business world and also its populair office 365 with the online email account should be taken in account.
So the type of client is really important to know if your recipient is even able to see you video.