If there is no such thing as credit, then the prices of all hard assets will collapse and it will become virtually impossible for poor and middle class people to own any of those assets. Because the only way a sale of a house (for example) could be completed is to find a buyer who has that cash available, and who wants to buy your house. How long would a seller have to wait for such a buyer to materialise? How long would you have to save to be able to buy a house?
Furthermore it would be difficult for the poor or middle-class to start their own businesses because how could you buy stock before you received and sales income without credit?
Money is a very ancient concept which we all understand intuitively, at least to a basic extent. If all the money in society was removed, some other form of money would immediately take its place - as can be seen in prisons.
Our modern monetary system has evolved over time to meet our needs. It is far from perfect, but it is a complex adaptive system. Making radical changes to a complex adaptive system is almost definitely going to result in unexpected negative results. So any such attempts should be made gradually and with great care IMO. And crucially, the changes should actually represent an overall improvement, not merely a change for some simplistic idealogical reason.
Inflation also is necessary to some extent because of the expanding population. The quantity of money must inflate to meet the needs of the larger population, as well as the increasing wealth of society over time.
Attempts to control money along idealogical principles tends to just result in a "black market" forming where people just find other ways to transact (although modern money laundering laws are trying to impose that control, with some success, but I'm not convinced this benefits the average person to any degree, apart from governments trying to track our money, so they can extract every last cent of taxation).