Bitcoin Forum

The whole point of POW is to secure the network with lots of hash calculations (hence the term 'work'). Phones have very little power (compared to asics, or even desktop cpu/gpu), so is it impossible for coins mined through phones to have any value and have a secure network at the same time.

actually the point of PoW is to secure the network with doing "work" not doing "a lot of work". technically there can be an algorithm that could be considered proof of work and doesn't require a lot of work to complete and still work.

the reason why mining (working) on your phone is stupid is that your phone is not designed to do that much work for long hours and without breaking.

That would result in a very weak blockchain which is prone to 51% attack and so on. Even with those 'easy algorithm' we should expect difficulty increase that will make at one point or another, mining with a phone will be useless as it doesn't produce enough hash to solve the puzzle.

Even in the beginning, you can use your old computer to mine Bitcoin and get some Bitcoin with it, and then it gradually grows to be more difficult and now CPU is no longer enough.

IMO there would be an equilibrium point where the increasing difficulty is not possible because there's no hardware capable of doing the calculation within the appropriate block time but there's not possible to decrease either because it could result in faster block time. Or in short, any PoW as long as it is used by people would eventually get enough security and rewards.

The only mining that can work on phones is through the following
Cloud mining,electroneum mobile miners are up to 170,000 people using the mobile miner presently and it works nice

I think it depends on how much you can mine. Theoretically speaking you can mine bitcoin with your mobile phone too, not like you are going to mine anything meaningful, it will probably have to be like a mobile phone pool where millions of phones all connected and maybe it can mine a a small number with help of some asics on top of that.

Hence, it is not about if it could be mined with mobile phone or not but its about if its making a dent in the hash or not. If couple of phones get together can provide a decent percent of the hashes even if at 1% of all hashes coming from mobile phone, than OP is right, its not feasible and not enough defense for someone trying to attack the network.

However, if it can be mined with mobile phone but its not practical and can't make a dollar out of it in 5 years type of low level than its fine.

And if you are saying like that and then you didn't even see how ETN works this day. i have tried it and i able to mine coin use phone but it's not worth to do that consider about that will be only burning our phone.
You can take a look at ETN and Picoin.