Cash is certainly necessary in the whole society, but as you say our money is always devaluating, it is believed that the encrypted currency will soon take over the model, and at least many people know that the money can be kept in the bitcoin.
Economy is not currency. Economy is part of the country growth. So if people will be growth country economy also growth. If need for the other country growth. First check the economy. It wil be give the country growth. So economy will growth in country. Business also improve and other country also invest and start the new business process. People growth is important of the economy growth. So bitcoin will be help to people future growth.
As our population grow higher everyday, it has also a large impact to our economy. People create, manipulate, and handle money. And if each and everyone of us has an interest on this, surely our economy will grow than the past years.