Ableton offers additional uses of MPE that you can use even if you dont have an MPE expressive controller.
As well as being able to manually create and edit MPE info in MIDI clips, which is a rather tedious process, there are also things such as:
The Ableton tuning system uses MPE to tune the individual notes.
There are some new MPE MIDI tools in Live 12.1 which I discuss here, which enable MPE messages to be used in clips in a few interesting ways without having to create this data manually: