It's kind of late to ask questions like this after spending 12 months of work.

Regardless of my other feedback, you should launch and see what happens. No one can predict the future.

That being said, I don't see who would be a target for your app. Vimeo Plus costs $10/month, Vimeo Pro $20/month. Youtube is free and allows embedding of videos in your own website.

Who are the people that would have a need for your app and wouldn't be served by Vimeo or Youtube?

At $500/mo you're in "enterprise sales" category. There's no way an individual or hobbyist will spend $6k/year just to upload the videos. Enterprise sales usually require enterprise sales tactics (picking up the phone, trying to convince real people about the value of the product) which pretty much means you need a (very good) sales team.

Also, at that price people will want to know you're a stable business.