plpythonu / using pg as an application server

PG 8.2

I am using plpythonu to add application server functionality to my
postgresql database.

For example, I have triggers and functions that FTP files, sends email,
processes files, etc..


Is there any good reason not to include this functionality directly in
the database? (Too much parallel processing, engine not equipped for
that kind of processing, threading issues...)


Thanks
Sim