A novice question regarding Ambari Technology Stack choice

I have a novice question that's been bothering me regarding Ambari Technology Stack , Ambari Server backend is written in Java (REST APIs); While Ambari Agents are in Python. *What benefits would have driven making the decision

BIGTOP Stack

All, In working on trunk, I noticed that changes are being backported to the BIGTOP stack in the source tree.  These changes appear to be changes to other stacks where a similar coding pattern is being followed in BIGTOP.  It is unclear if any of these changes are breaking the stack or not.