If inflation is used as a tactic, then many countries will experience problems, unless a country tries to have an economic impact on other countries. They will try to suppress the currency of a particular country with existing policies and if a country's currency weakens then it will be quite risky.
It is needed, it doesn't create problem for the society at a small level, you need to think of high inflation. If you have it at 20% then yeah it's a problem, if you have it something more than that (which some nations do) then it's even a bigger issue, but if we are talking about 2-3% then we are talking about something that is good for the growth and you should have it.
Zero inflation means that there is no growth and that would mean that the nation has a stagnant economy and that would not help anyone, big companies would just earn more money and everyone else would lose. Growth is needed so that big companies would get that growth, and you would get a little bit as well, and everyone would profit from that situation.