Late Reply: This is going to sound harsh but it's true. I wouldn't miss it. If Beehaw disappeared tomorrow I probably wouldn't even notice, and I'm sure that would be the case for many other people here. The problem is that because Beehaw has defederated so aggressively from the largest instances and shut its doors to new users, and people just moved on, or didn't notice or care. I spent most of my first days on Lemmy.world and consequently didn't see a majority of the content from Beehaw, but I did see many upset users who had to Migrate from Beehaw due to the defederations since most of the content and communities they wanted access to wasn't available to them on Beehaw.
Since Beehaw didn't (and still doesn't) have community creation enabled it never really had niche communities like other instances did, it is rather forgettable because of that, what most people will remember it for though is the defederations and having to migrate accounts to not be cut off from the rest of the fediverse.