I can't give up my iPhone for that very reason. I need apps like Auxy, ElasticDrums, Launchpad, GarageBand etc. The same reason Android users love their OS- because you can do a lot on their phones, I need these apps to keep my juices flowing. Simple app like Auxy can keep me occupied for hours on end.
Auxy is amazing. Been using it for a couple weeks; hands down the best designed, best sounding, fastest and most inspiring music app I've ever used. I've also been putting some tracks together. This one just came out yesterday: http://auxy.co/track/ZMbYiJu52f3I. Love your track, just shows me more possibilities this app gives us. If they give us an LFO generator, basic automation, time signature change, simple pattern saving and hide all these features behind a $10 paywall, I'm getting it. Truly amazing!!
It's a simple and fun app but if you have an iPad, there's a similar app called Auxy which unfortunately is iPad only. It's not quite as minimal as Drummer but it's just as much fun plus it does a bit more. Best of all, it's also free: