To be totally honest, I'm not sure either, as I had only minimal experience with Scala prior to that, so I don't know how much my anecdote is worth. :) I found IDEA fine for Android development, but I also didn't even try Android Studio, so I don't have anything to compare it to. That said, the little server-side Scala work I've done seemed to be a little more seamless than Scala with Android. It's been a while, so I don't remember the details, but I'm pretty sure little things like compile-on-save worked just fine in IDEA for normal Scala development, but didn't work at all (for me at least) with Android. You're also likely going to run into problems replacing Gradle with SBT (assuming that's the path you take), since Gradle is the official build tool and has all the mindshare; if you run into an Android-specific problem with SBT, you're most likely on your own, given that so few Android devs use Scala. IIRC, I had a few issues getting multidex to work because the Scala-on-Android guide I was following was out of date.

I would say that if you're already familiar with Scala and aren't afraid of getting into the weeds a little bit, you should be fine in the short-term. My personal fear is simply that, especially with Scala 2.12 dropping support for Java 6, Scala development on Android doesn't have a clear future, so as Google changes their build stack, you may find it increasingly harder over time to keep all the tools working.