And every year, it'll change. Eg: myawesomedomain2023.com for next year. The old domain would all redirect to the newest one.
This sounds cool to me but what are the downsides? There's obviously the cost factor. And I imagine it wouldn't be the best for SEO? Are there other downsides?
Sounds like a big hassle for small novelty.
Of course there are well-established URLs, e.g. 9to5linux.com, that can get away with it but given a site that I didn't already know about with numerals in it, I wouldn't click the link, personally. But like I said, that's just me. Perhaps your site would be in the Top 20 most visited in the world for all I know.
Seems like a lot of work that could be better spent creating awesome content.