Honestly I don’t think there is a reason, there aren’t many features for viewers on there and it’s just another account to deal with. You can subscribe to accounts / channels from Lemmy or Mastodon or presumably whatever other Fedi service you’re already on, and leave comments / upvotes from there.
The search function on a given PT instance is only going to return results it’s federated with so I think the only way to get a “global” search and find things across all the instances at once is https://search.joinpeertube.org
Honestly I don’t think there is a reason, there aren’t many features for viewers on there and it’s just another account to deal with. You can subscribe to accounts / channels from Lemmy or Mastodon or presumably whatever other Fedi service you’re already on, and leave comments / upvotes from there.
The search function on a given PT instance is only going to return results it’s federated with so I think the only way to get a “global” search and find things across all the instances at once is https://search.joinpeertube.org