It is something to think about. Why should mining only be acceptable on desktops and other hardware? Phones are online pretty much all the time, they can mine some.

Yes, that would actually be very good if we can mine using out phones. However, we should have very powerful phones tgen with very high specifications in order to solve complex strings of codes. As of the moment, we can somewhat still use our phones for doing signature campaigns or even fb or twitter campaigns.

i am using monerominer and minergate. over the years i have collected several decent android phones and converted them into mobile mining. in my experience.. phones can mine but will require enough patience, as it takes a lot of time to mine 1 coin. however i am not taking a way the possibility that phones can faster mine in the future. maybe future phones will release selling points on their phones that i can be use for mining producing this number of hashes. well phones makers are not yet looking to that perspective as of today. but future of mobile device might include this. just like motherboards of the past they never think it can be used for mining but today a lot of motherboard companies are creating motherboards which is used for mining. so i am not taking the possibility of phone mining in our futur device.

The only way to make this profitable is using a cell phone that you don't use to call, and charge it with solar power.
But even in this way, I doubt it will be a good idea.

Recently I saw some of the startups starting  mining in mobile and those are Electronum and may be many in future. But it will not be feasible at all because most of the mobiles are vulnerable

Yes, of course. As far as I know there are already some projects which allow mining on the phone. This is a very promising and interesting.

Yes, more people able to use, more chance for it become the currency for every transaction.

I doubt if that is possible, mining rig minimum requirement is vga, without which mining  won't run, and mobile devices don't have this feature.

I agree ! Not only that, the battery will quickly run out !still and iron will get tired and die!