Re-read my prior post. I just discovered a new flaw in Iota.
[1] Make sure you understand the implications of this. Seems to me that Iota's mining can be outsourced to ASICS, thus Iota's mining will economically centralize same as for Bitcoin!
There are no fees in Iota to encourage centralised mining. The reason they have this non-signing policy is because transactions can become orphaned, therefore unless they expect the payers to continually monitor the tangle and re-send any orphaned transactions, 'others' must be required to do that job for them....
I think you missed my point, which is that if the PoW can be outsourced, then it is always more economical to do it on an ASIC farm near to cheap hydropower. Thus the mining PoW in Iota will trend to professional miners same as for Satoshi's design! They haven't accomplished anything at all on economic centralization (but have accomplished scaling but with other critical flaw I asserted upthread) because the economics of mining remains centralizing!
Note as we transition to mobile, battery life is important to users. Not needing to waste battery life on frequent microtransaction PoW computations would be desirable. Even IoT devices are often necessarily low powered. My design will face the same economic reality, but as I said if the latency cost is much higher than the cost to compute the PoW locally, then my design principle holds because in my decentralized, permissionless design the payer signs the PoW thus to outsource it would require a round-trip network communication (and wireless network communications consume battery life also).
It was never clear to me what incentive there is for anyone to redo that work, though.
If you don't understand the incentive to redo the PoW share for each Iota transaction, then please re-read the
upthread discussion where in one of the other attacks on Iota that I contemplated (and posted about), CfB explained that attack could only be thwarted by allowing PoW shares to be recomputed without forcing them to be resigned. I understood why in the context of the upthread discussion with CfB. I prefer to not rediscuss the reasoning again (redundant, makes the thread too long, and my time/energy is scarce).