From Quantnet Wiki
[edit] Python in Quantitative Finance
Python, generally beloved by those who use it, plays only a small role among quants. It seems to be considered a "prototyping" language as a bridge from algorithm to "real" code in C++. Like other scripted languages (including Perl and UNIX command line tools such as sed/awk and grep), it is used primarily for data gathering as opposed to trading.
One serious drawback of weakly-typed languages, particularly scripted languages like Python and Perl, is that typing errors are found during run-time, rather than during compilation. This can create costly problems when critical software is not subjected to sufficient debugging.