Can you mix elements of 5 or 6 tracks at once?
Can you re-sequence tracks on the fly so that (e.g.) you have a breakdown last twice as long as it might do normally, off the cuff?
Can you jig it so that you hit the drop of 3 tracks simultenously at the click of a button?
Can you trivially add your own drum loops and acid lines in real time?
Can you sample your voice, chop it up into transients, apply the groove template of some other loop that's running and then bring it in as a texture - completely improvised?
Seriously, there are things you can do with Ableton you couldn't hope to do with vinyl. You can get close using CD decks with cue & loop points, but it's still not quite as flexible.
If you can't imagine stuff you could do with Ableton that you couldn't do with decks then you're just not thinking very hard.