There's nothing wrong with using multiple Digital Audio Workstations - I think it makes you more versatile and what if a situation came up where you had to use a DAW you had no idea how to work. As someone whos just learning Live 9 after using Reason, Reaper & FL Studio for ever - every new DAW changes the way I think about making music.
Plus Live was esp. made for Live performances, another good reason someone would own Live and another DAW. Why discard the old for the new?
Also, It doesn't matter what you have, it's how you use it!
I've Reason, Reaper, Live 9 Suite, MPC's Daw, FL Studio and hell I even cut most my vocal samples up in Audacity! Just because its simple, find your sample, cut, delete, paste - boom done any tweaking eq etc I can do in another program.
Some of them are really similar but the ones that stand out are nothing alike. Look at Propellerheads Reason - it's like having a rackmount on your PC - compared to FL Studio then to Pro Tools** & Reaper then to Live. It's like day and night [besides Reaper & PT...lol] and I'd still like to play around with Sony's Acid & Bitwig.
**Industry standard or not; Reaper vs PT = Cockos Reaper wins [I esp love that its open source - so anyone who knows what they're doing can modify reaper and they'll add it to the official program, and updates are constant - thats the way to make amazing DAWs/Controllers - let the smart fans fix and improve it - instead of letting the "IT Professionals"

MAYBE fix it...you know when they get around to it, or just wait for Live 10 and Push 3!!
I love my Push 2 & Live 9, but theres alotta Push issues that need to be addressed... like shoulda been day 1 patch addessed - not being able to use alot of the plugins that come with Live! Not even talking about packs/racks bought from the store comes with the software.
Peace