This seems to put a premium on resiliency, or at least forces you to take it into consideration as part of 'cost.' For example, a troll can throw itself off a bridge at the risk of broken bones all day long. There's still a real cost there, the injuries still happen, they just heal in moments compared to a human who might be invalid for weeks or even permanently crippled. Presumably this would apply to mental/emotional costs as well, which is incredibly difficult to handle in game, because how do you measure the mental resiliency of a PC?Effectively, one makes personal progress in getting stronger by taking on risk. And it has to be genuine risk--doing something risky (high cost of failure) but with very low probability of failure, or taking safeguards to either reduce the cost or reduce the probability of failure diminishes your return.
This effects more than adventurers though. It means people who have professions that are greater risk gain more power than those that are not simply by going through everyday life. That means you have to try and quantity every job by risk because you've created a tiered structure of social classes based on job risk.This is a thought I had to explain why adventurers seem to grow more powerful more quickly than most. Basically, by taking on higher risk than normal, they get higher growth. And those who "play it safe" do so in exchange for fast growth. On the other hand, I'd expect that you'd see a lot more people burn out quickly by taking on more risk than they could handle. And a higher culture of risk taking, at least in parts of the culture.