http://www.python.org/doc/2.5/lib/node46.html has 

compile(pattern[, flags])
Compile a regular expression pattern into a regular expression object, which can be used for matching using its match() and search() methods, described below.

This could be read as implying that the regular expression object can ONLY be used for matching using the match() and search() methods.

In fact, I believe it can be used wherever "pattern" is mentioned.