It matters more on peertube, but also less.

I’ll start with why it matters less. You can interact with peertube via mastodon. You can subscribe to channels and leave comments on videos with those accounts. But, you will not be able to login to a sever via the peertube app. And to be honest, you’re not missing much there.

Why it matters more if you genuinely want a peertube server account…

Most peertube servers are accepting only accounts that are going to generate content. So if you aren’t planning to post videos you have to find a server with open sign-ups. There are also peertube servers that do not federate.

If you do want to post videos it matters in many ways. Does the server want the content you will be posting? Many peertube instances are themed towards specific genres or topics. Does the instance have upload limits? Are you required to contribute to server costs? Etc…

Essentially, peertube requires a lot more research before signing up. There are a lot of caveats. It’s also a horrible place for discoverability and the app integration is janky at best. The only thing it really shares in common with Youtube is that you can watch videos on it.

Edit: bonus catch, does your server stay updated so you can use it with the peertube app?