Currency is a fine way to represent value, but a currency that's being inflated is certainly a worse way than a currency that isn't. If a government plans to inflate its way out of debt, the markets respond to that by trying to charge higher interest, but ultimately governments (outside the eurozone) control their own currencies and their own inflation statistics, so the markets are always playing catchup.

A truly risk free currency would be a currency that couldn't be inflated by a government to escape from its debts, like a cryptocurrency (if they actually worked).