When is inflation a good thing?

Recently while discussing bitcoin I've come across several individuals who say inflation is good for an economy. I cannot get an argument out of these people for why it would be a good thing, they seem to have been taught it was good and hold that belief without really knowing why.

Someone play devil's advocate for me and tell me the best argument for why inflation is good. I can't think of any reason it would be good and am blown away by the fact some people think it's good. Until recently I'd not met anyone who thought it was a good thing.

Of course my rebuttal is always about how inflation means reckless gov debt and it devalues the currency, but I'm wondering if there is a better argument from my point of view.

What do you guys say?