wildbunny

You cannot have a trustless consensus without a mining incentive:

Quoted from my post linked below:

o) Network hashrate is the overall power of the network - in bitcoin, this is the computing power needed to generate a block.

o) Bitcoin employs a mining reward which creates a competition between miners to produce a block and claim their reward for doing so. Slower miners lose out to faster miners, but they still participate in the competition to produce a block because they stand a chance of winning occasionally.

o) This mining subsidy provides a positive incentive to miners to play by the rules, and encourages them not try to double spending, because they might as well claim the mining reward instead of trying to double spend which is often much more difficult than producing a single block.

o) The mining subsidy also encourages all miners to participate in the mining process, which gives an overall metric for total network hashing power, which you can then use to give an estimate of when it is safe to accept a transaction of a given size, as confirmed, because (on average), the block reward is equal to the electricity cost of mining that block. That means that when your transaction has been buried under enough blocks that the mining subsidy equals the transactions size, it is more or less safe to accept that transaction as confirmed.

Now, imagine the situation with no mining reward.

o) Instead of participating in a competition to win the block reward, miners have no positive incentive to participate anymore. They now are left with the negative incentive to try and double spend.

o) Since these miners are not contributing their hashing power to the network anymore, the overall hashrate of the network in unmeasurable, since these miners are quite likely to leave their ASICs in sleep mode until they want to double spend

o) With the network hash rate unmeasurable, there is no way to put an estimate on when it is safe to accept a transaction as confirmed.

When there is no way to estimate when it is safe to accept a transaction as confirmed, that currency is now useless because any transaction can potentially be reversed.

This is why both byteball and iota use trusted third parties to secure the network, but at that point, you might as well be using VISA.