Abelton even if you're not synth based?
Or is it that all new users are synth based?
Yes.
And...kind of?
Ableton's big feature is the clip view, which is kind of loosely based a tracker, and you probably think of clips as being loops. But, it's probably more flexible than you think. Clips can be audio or midi, any length, don't actually have to loop, etc.. They can have follow actions to stop or move on to the next clip in the channel, and a bunch of other stuff.
Yes, a
lot of people use it for electronic music based on synths & samplers (the big version comes with several good synths and a couple very good samplers), but not exclusively. It's also a really great workflow for sketching out songs when you have pieces but not the whole arrangement. And whether you're recording audio or programming synths, you can play the sections in real time (and record the "controls" to be edited later)
and jam along with them (while recording). It's a different way of making a song out of pieces than dragging them around a timeline.
You also don't
have to use clip view at all. It also has a normal linear timeline view and can work with audio just fine.
I don't know if they're still doing it, and it's probably not the best example, but Depeche Mode at least used to run their live show off Ableton Live. My understanding was that it was largely for flexibility - they could play samples or recorded parts and keep things in time easily. Plus, clips don't actually have to contain audio or MIDI notes - you can use them just to fire off automations. So you can do things like record the automation for a reverb throw...start it with one key/midi press...let Live keep it in time with the master time...which you can adapt to a live drummer via tap tempo...
while processing all the sound for the live show....and you can let the band do things like repeat sections (e.g., "hey, let's play this chorus again") at a moment's notice even when you're playing with "a tape" for some of the parts or effects automations or anything else it can do. And instead of just reverb throws...you can do that with literally any bult-in or plugin effect...or anything else that is recorded audio or can be controlled via MIDI.
It is (or at least can be) a different way of working, but it's
really flexible.
I honestly wouldn't be surprised if there were more commercial controllers made to work with Live than Pro Tools.