As we all know that mining requires a powerful equipment to be able to mine more bitcoin in a certain period time, then I think smartphones are not capable of doing that. Bitcoin mining in mobile might only cause your smartphones to get damaged or broken. If there are instances that you can mine bitcoin from smartphones, I believe it is not that profitable. A smartphone is probably best used for its original purpose only.
I think it is not wise because technological developments in the future of smartphones can also be used for bitcoin mining, but of course that will also affect the price of bitcoin
I think if bitcoin can be mined using a smartphone it certainly requires smartphone specifications that are very capable, because if we only use PC mining, we need a large VGA specification