Very common unfortunately. Sometimes it also claims to make it safer for the end user because it can filter out bad sites (?).
But yeah, definitely more data points for the platform.
BTW, Google Search also does this and probably other search engines too.
Always hover before you click to see what’s behind it.

Sounds like a way for bluesky to track all putbound clicks and then slice it up in some sort of admin tool for each brand operator to view their referrals from bluesky inside bluesky. That’s as opposed to using the natural referer (sic) http header that would allow the brands to track the stats themselves on their own servers.

Google has been doing this deliberately for years (maybe forever I forget when they pulled the rug on the referer header)