People would make irrational choices, certainly in deciding whether to drive or fly. I don't think the market would come up with an equilibrium price for a micromort: at best you could find an equilibrium price for taking some risk of dying in a particular way such as a high-profile airliner crash.

Also, it's hard for even an expert to estimate the current chance of a 737 MAX flight crashing: historically it's around 1 in 5,000, but if they were cleared to fly tomorrow it's hard to say if the rate would be 1 in 10,000 or 1 in 1 million.