Here are some reasons why:

• Over the years, I’ve been slowly convinced that whatever the language you program in your professional life, learning new languages is an asset as it change the way you design your code.
  For example, the excellent LambdaJ library gave me an excellent overview of how functional programming can be leveraged to ease manipulation of collections in Java.
• Despite my pessimistic predictions toward how Scala can penetrate mainstream enterprises, I still see the language as being a strong asset in small companies with high-level developers. I do not wish to be left out of this potential market.
• The course if offered by Martin Odersky himself, meaning I get data directly from the language creator. I guess one cannot hope for a better teacher than him.
• Being a developer means you’ve to keep in touch with the way the world is going. And the current trend is revolutions everyday. Think about how nobody speak about Big Data 3 or 4 years ago. Or how at the time, you developed your UI layer with Flex. Amazing how things are changing, and changing faster and faster. You’d better keep the rythm…
• The course is free!
• There’s the course, of course, but there are also a weekly assignment, each being assigned a score. Those assignments fill the gap in most online courses, where you lose motivation with each passing day: this way, the regular challenge ensures a longer commitment.
• Given that some of my colleagues have also enrolled in the course, there’s some level of competition (friendly, of course). This is most elating and enables each of us not only to search for a solution, but spend time looking for the most elegant one.
• The final reason is that I’m a geek. I love learning new concepts and new ways to do things. In this case, the concept is functional programming and the way is Scala. Other alternatives are also available: Haskell, Lisp, Erlang or F#. For me, Scala has the advantage of being able to be run on the JVM.

In conclusion, I cannot recommend you enough to do likewise, there are so many reasons to choose from!

Note: I also just stumbled upon this Git kata; an area where I also have considerable progress to make.

From http://blog.frankel.ch/why-i-enrolled-in-an-online-scala-course