Yeah we should certainly explore the security implications of the VRF implemented at the Bitcoin layer vs Stacks layer. BTW, the dust fee mining is sort of similar to GM-Chung’s idea i.e., instead of a cap on all bids, it places a cap on bids for 10% of the rewards and the cap is very low: a dust transaction.
What this effectively achieves is that it caps the potential negative impact on the stacking yield. The bulk of the mining dynamics (the 90% of the dynamics) remain the same but the “small miners” are grouped into a new category where they can mine with just BTC fee i.e., just a dust bid.
If you compare this to the idea of capping all bids, then the main difference is that capping all bids can lead to a situation where the stacking yield can drop a lot (a lot more BTC starts going to BTC fees than getting used as BTC rewards). However, with the “dust fee mining” proposal that maximum reduction in the stacking rewards is capped at 10%. However, it can still lead to 100+ new miners.
The math for that is simple. At the rate of 1000 STX per block, you’d allocate 10% i.e., 100 STX per block to the dust fee miners. That’s approx $100 USD per block at STX price of $1. Bitcoin average fees can be lower than $1 these days. (At higher BTC fees, say $2 per transaction you’d see approx 50 miners.) More importantly, as the network grows, at higher STX price the capacity to support more miners goes up even more. I think the discussion for the SIP of adjusting emissions in the bootstrapping phase (coming years) is also relevant here. Because if a SIP like this is adopted and the stacking yield takes a hit then it’d be nice to compensate for it by increasing the stacking yield for the coming years as well. The Bitcoin yield is a truly unique feature of the Stacks network and a high BTC yield attracts a lot of new developers and users to the network. We haven’t started fully tapping into the power of the BTC yield concept. Maintaining a healthy BTC yield in the coming years is important, especially as the network reaches escape velocity.