Is mining with mobile device a profitable venture today? I read a bit about this and learned that Monero maybe worth mining. then there's Electroneum as well. I wanted to know from other's experience.
One might ask why spend on buying phones. Instead get a PC. Thing is I have few old phones that I can't sell, I want to see possibility of getting some cost back before giving/throwing them away
at this total network size, anything less than a dedicated mining device is ultimately a waste of time

you just wont be able to compete with a device designed to hash; your device is essentially emulating the same process. dont do this. besides being inefficient, using your device in this manner will degrade it prematurely. they arent designed for the load the emulation process puts on a non dedicated device.