After the developer has updated the branding with the subtle Playable logo at the end of the video, I can give it 5 tacos without reservation.
The tool is exceptionally easy to use and doesn't require any learning curve.
Basically, you upload your short video (10-30 sec), indicate the URL you want the video to point to when someone clicks on it, copy the code for your email marketing software and paste it. That's it.
I don't have data yet to see how much it increases the engagement, but I am confident it does what it says it does. You need to be blind not to realize that the email campaign with the embedded video is more engaging than the static one.

Regarding some comments from sumolings about the whitelabel. Guys, I don't know about you, but I personally don't want to be a life-time burden to anybody and therefore, I will be happy to show some support to the developer and display the Playable logo when sending our email campaigns and hopefully, they can get some new customers as a result. And if at some point we need a fully whitelabel solution, then $10 a month is a fair price to pay in my opinion. Thanks for bringing such a great product to AppSumo community.