Why use Kbin over Mastodon to post a microblog to the Fediverse? Genuinely curious!
There were so many times I was browsing reddit and thought to myself, "this didn't deserve a post of its own." Was it content related to the subreddit? Absolutely. But it was simple, trite, repetitive - for example, just someone having a halfway neat experience in a game, but with an incident for which the novelty had worn thin for long-term players long ago. (oh so your taming inspiration lined up with a thrumbo passing, wao sugoi moving on....)
On the flip side, I'd often want to share my inane thoughts about a topic with others interested in that topic, but I knew my inane thoughts didn't really warrant a whole post. Sometimes I just wanted to say "I thought this event story was neat" without adding a "what did you think?" and massaging whatever discussion thread followed.
So, in short, I had a higher standard for what counted as discussion-worthy and was dissatisfied when both consuming and producing content because of it.
The kbin magazine blend of discussion threads and microblogs is perfect for this sort of problem, in my opinion, which is why kbin is my ideal setup. You clearly define when you want to make a discussion space for everyone vs. when you want to just bounce a thought into other like-minded people simply by whether you create a thread or a microblog, and you don't need two different sites (reddit/twitter, or lemmy/mastodon) to do it.