It might indeed happen that the risk appetite suggested by 0% inflation is not optimal. But that just begs the question of who gets the newly printed money. Currently people with political or banking connections get it so they get richer and richer.

In the blockchain context only one answer is meaningful: the miners. But then if we all decide that 2% inflation would be optimal to encourage risk taking, then mining would be extra super profitable. Right now bitcoin's inflation is under 2% and people already complain about its energy footprint. Imagine now that bitcoin is all the money and the inflation is 2%, that's how profitable mining is. Then the question will be, why would anybody do anything except mining?

You might say lets do PoS instead. But PoS only pretends to be inflationary. Renormalize it by dividing everything by 1.02 (assuming 2% inflation) to the power of time and you will see that it's just tax on people who neither run a node nor delegate their money to one.

There is also Monero that is a PoW coin with linearly increasing money supply. That's fine but it's equivalent to 0% inflation target anyway, just approaching the target for an infinitely long time.