In the future (also already now with Java), Python and Java applications can be faster and use less battery energy than same applications (in certail family) written in C/C++. There is optimizations available for these higher level languages which are not possible for standard c/C++.

Read the study: http://trs-new.jpl.nasa.gov/dspace/handle/2014/18351
Also other studies and benchmark tests found with Google.