I guess, it is profitable although the profits are relatively small as we just use the mobile which is the only cost and no hardware cost or other operational cost. It takes loads of patience like earning steem on musing or steemit. Slowly it adds up.
I am growing my satoshis using www.bitfun.co where after every three minutes one satoshi is given. In a bout a day of gathering satoshis, i guess on average it take many hours to create that many satoshis. But i only do it when i am free. I just press to claim satoshis which can be converted to bitcoins.
Free things need time to earn. I guess everything has a price. It is still not too late to mine some amounts of bitcoins even if those coins are not much. Maybe one day bitcoin will shoot up in price again and those little bitcoins we earn can get us something.