I highly recommend YouTube. You can configure the embed video to hide the YouTube watermark, autoplay, hide the controls, and hide all related videos (that show up after the video is done playing). This will make your video look amazing on your launch page.
Here is a link on how to configure the YouTube embed code parameters - https://developers.google.com/youtube/player_parameters
If you do your keyword research and optimize the Title, Description, and Tags when uploading to YouTube you can take advantage of more search traffic from Google and YouTube.
What is your goal with this video? Do you want it to live on your lauch page only? Or do you want it to get noticed in other places on the web as well? Do you want the video to get shared around social media, for example? Or embedded into other people's websites?
First ask yourself: Does my video even work without the context of my launch page?
If it does why not go with YouTube. If you set up your video correctly you'll be rewarded with a decent Google ranking as well as with lots of YouTube's search traffic. After all YouTube is the second largest search engine.
You'll also benefit from YouTube's related video algorithm which can bring in a decent amount of traffic.
And you can profit from YouTube's sharing functionalities. Over the years people have simply learned how to share a YouTube video. It's natural.