Agreed. Groovy is in my opinion absolutely the nicest and friendliest language to read or write. Scala has some really cool features that I would love to see in other languages, but it also has a tendency to become somewhat unreadable and is a lot harder to get into when you're new to it.

Groovy is gaining popularity among scientists and researchers because of it's ease of use and performance.

Really? I've been using it but I feel pretty lonely. I ended up creating my own Groovy based version of R / pandas data frames because there is simply nothing out there. I'm curious in what ways you're seeing it used.