I agree, the karma count was not something that I wanted to see either.
Here is a link to the post from the Dev about being a tester and early access for the Boost app. It contains a link to sign up for it.
Also, these new communities that I have joined since using the Boost app are not showing the instance name in my list of communities.
As the title says, when I join a new community using the Boost app, and then later try to go to that community, I'm getting an error message "404 couldn't find community". Any community that I had already joined before using Boost, I'm not having this issue.
Edit: I did find a workaround for this problem. If you click on the three dots at the top of the community list, then click on Refresh. This seems to fix the problem.
Boost is probably just going to be an Android app, since Boost for Reddit was also Android only. I wasn't sure if the app you were talking about, Memmy, was an IOS app.
Did you ever use the official Reddit app? I personally do not like it very much. The third-party Reddit apps were just a whole lot better, at least in my opinion and others. Apps like Boost and Sync were both very popular Reddit apps, but have both now moved on to Lemmy.
Boost for Reddit was a very popular third-party Reddit app. After Reddit's API changes, causing the third-party apps to shut down, the Boost developer is now making an app for Lemmy.
The Dev said in another comment that he expected to release it by the end of August.