I mean that's fair : value is relative.

The main value of Nebula is no ads. I have YouTube on Firefox with uBlock Origin, so no ads either, but shitty performance due to YouTube fighting the AdBlocker. But more importantly I don't think the ability to watch YouTube with no ads is a given, so I want to have a viable alternative.

And secondly, I want to support the creators and a platform that sees me as a customer, not as a data-cow to be milked.

I'm sure Nebula will eventually have a free tier, but that can incur high costs and degrade the experience for paying users. They'll do it when they feel comfortable.