I think that inflation has a very significant downside: it makes most contracts spanning a period of time difficult. That said let me describe a scenario where I would be tempted to inflate if I were running a central bank.
A classic recession where there are idle factories and idle workers who would like to consume more but lack the money. Milton Friedman introduced the term “helicopter money”, perhaps jocularly, to describe the printing of new money and distributing it randomly to the population. This is clearly inflationary. Some economists have said that when you feel poor, you are likely to save a small windfall for even harder times. With the prospect of inflation, however, you feel you must spend the money while it is still worth something. The recipients of the helicopter money are thus to quickly buy goods, perhaps mainly durable goods. Production and hiring will follow.
Another root objection to printing money is that it puts the allocation of resources in the hands the government leading to a form of central planning. This transfer is called seigniorage and is very much like a tax. Helicopter money, on the other hand, involves no seigniorage and consequent central planning!