If money is immediately costless to produce for the entity producing it, there is still a cost and it's born by everyone else. It must be accompanied by an increase in desired goods and services to retain value. If the entity that creates the money uses it to create more value than the inflation it causes then this is a good outcome. Otherwise if the money is created to pay for unproductive behaviour like funding big wasteful armies or propping up asset bubbles, then money will ultimately become worthless and society loses, especially if the originator(s) of new money or derived credit get bailed-out, socializing the losses.

Giving money/credit creation some friction should help prevent asset bubbles: Feedback loops that get going when new money bids up collateral, which is borrowed against to create loans to bid up collateral further etc. But there are many ways to do this, and I agree that subsidizing rich people with a 'risk-free' rate of return on government bonds is not very fair or effective.