Small but steady inflation is good. The macroeconomic fear is that people will just hold onto their money in the form of raw currency. That’s bad. Currency is for a more convenient representation of value. I can’t compensate a roofer in computer code, so currency is a stand-in. But it also shouldn’t languish or else the economy stagnates. The world used to regularly experience zero inflation or deflation, which hurt the economy. As much as we’ve had some instability lately, things are nowhere near as bad as they could be.
Of course the flip side - hyperinflation - is also bad, but that’s not what we’re talking about here.