One obvious advantage of using extensions is the performance improvement.
Considering the examples we went through, the time taken to calculate
factorials (which fit in int data type) was about 100 times faster than
a traditional Python method delivering the same functionality (since the
code gets already compiled). Another advantage is that extensions can act like
a glue for programs written in C and Python. For example, if we have some code
written in C and want to re-use its functionality in Python, we can simply
write Python extensions for that code instead of porting it to Python by
re-writing the functionality in the latter language.