My concern is that DRKs will be so rare that the Proof of Service will be nullified and it will become a Proof of Stake in an unused coin...
Such extreme lack of liquidity will make it hard to get in. Even small buys will price themselves out and walk away instead. And that leaves you in a position of not actually providing a service because nobody is using it; Proof of Stake.
Same amount of work for the node processing 100DRK lumps, 1DRK lumps, 100Duff lumps, 1Duff lumps.
Integer DRK will be expensive, doesn't matter, we have 8 places worth of Duffs after the point.
"Not enough liquidity!" = "I can't buy as much as cheap as I want!" Guess what, you want more, you gotta pay...

Cute, but you're missing my point.
If people can't even buy a useful amount of it to use, people who want to use it as a currency, not a "to da moon" ticket, how will it get adopted? What service is being provided to all the nobody not using it? If I want to use DRK to buy something that costs $5, but trying to buy $5 worth of DRK results in my pricing out my own order, and having to pay $7 to get it... I'm just not going to do it. This will increase volatility as well...
It becomes a PoS holder coin pretending to provide a service, but nobody uses it... So there is no service. It's just proof of stake from mining blocks... PPC manages to prove how useless that is without all the complication of MNs and mining and taxation trolls... It's like a big circle jerk just to end up, functionally, being nearly the same thing as PPC...
I'm looking at it from the perspective of using it as it is supposed to be used, not the "to da moon" mentality.