... it really looks like you don't need it.
I made a few tests today, checking the latitude you get with different styles.
The results were amazing; Canon's contrasty "Standard" style gives you 7 stops of latitude, Technicolor records 9, i.e. 2 stops more in the shadows, BUT:
Canon's own Neutral style, with contrast set to minimum, can record 10 stops! This is evident if you lift the black level in post to the same dark grey (approx. 15-17) that Technicolor uses (for some strange reason...)
If you drop Technicolor's black to 1, it looks just the same as the Neutral style at minimum contrast...
Go figure - but look at this little test image, shot from a set of ND filters, assembled to a 12-stop scale. All exposures were exactly the same, the only change was in the "style":
So, it looks like the only difference between "Neutral" and "Cinestyle" is the boosted blacks in the latter. But that's easy to achieve in post from the Neutral style.
Load this image into a photo program, and use the eyedropper to check the values of the different patches - I did, the differences are minimal.
PS: Note that the jpg compression may have lost some of the finer shades in this test...