I've adapted the same work flow as well. It's really nice to have one script that generates data (often taking a few minutes or hours) and then another (in TeX) that configures display. That way when I recycle plots from papers into slides for a talk, I can reconfigure these easily.
Tikz falls short when you have thousands of data points and/or need to do some scripting or filtering of the data. Scripting things is much nicer in Python than TeX.