Sure ... it seems they were making a DM app for their platform and realised that it could be good as a standalone app.

Part of the picture for them is that pixelfed has started to experiment with transferable IDs or authentication, so that you can signup to pixelfed straight with a pre-existing mastodon account. It seems that want the same for this app. So the idea, I'm guessing, would be that if you want to start DMing with someone you know over the fediverse, you can go straight to this app, sign in straight away with your fediverse credentials, get your usual alias and find your friends with their same aliases. If true, I'd imagine that'd make it easier to sort side-load the app with any particular instance.