It's no secret that the number of people using mobile phones far exceed those using computers. That should make cryptocurrencies mineable with a phone much more decentralized. The problem is that phones don't have the same computing power as an ordinary PC. With such limitations, it'll be impossible to turn a profit when mining any CPU-based coin on a mobile device. While some coins just simulate the mining process (eg: Electroneum), there are some which actually use your phone's processor to the max.
I believe Magi (XMG) is one of the best (if not the best) coins you can easily mine on your phone because of its unique PoW algorithm. It penalizes big miners by reducing the block reward. Effectively, the "little guy" gets the most coins per block, while the others are left behind in the dust. Not only this enables true decentralization, but it also makes the Blockchain more equal to everyone. I'm beginning to explore Verus which is a coin that can be mined with CPUs. Both Monero and Wownero are also CPU-based, but they're much harder to mine because there are GPUs on the network. Ultimately, it's all about which coins give you the "most bang for your buck". If you're only doing this for fun, then I'd see why you can't mine with a phone in the first place. Just my thoughts

That is because mobile phones are thrice cheaper than the computers plus they are more portable. You cant carry your computer outside and the best part is that mobile phones are now more powerful than the standard computers. This is why projects like the one the op is talking about are now being implemented. That magi (xmg) you shared there is also cool. Didn't knew that there are projects like that who exist who favours small miners than the big miners.
I think the inventor of it was once a small miner and he invented it as a revenge to the big miners. If the coin's value isn't big then we can say that we are doing it for fun but who knows, what if it grew a lot someday?