I'm still thinking on how it will be possible to run the app on IOS. 
Except for side loading I don't see a way. 
Can the dev's comment on this please? 
you'll probably be able to do it by jailbreaking your phone. that how everything else that isn't approved by apple works.
Yes and if you have a warranty case your warranty isn't working anylonger. Also you go on risk to break your phone by jailbreaking 
 I still don't think there will be a big userbase for Apple especially not big enough to get developers working on apps for this. But maybe for Android there is one.
Well you no longer need to jailbreak. There's an official way to side load apps on IOS now. 
But as stated before, only techies will do that .. I don't see regular users doing those technical things.. 
Even if this is true installing applications on Android devices will be always easier 
Yes, install stuff on Android is much more easier then on iPhone when it comes to not store related apps. For me, I would never install something not checked by the App store on my iPhone because you never know what you will get as an extra suprise. In worst case you can't even make use of your warranty as you not went through the official way.