Cash ISA savings rates are looking pretty attractive right now. That's not going to happen now as the war with Iran threatens another oil price and inflation shock. That's comfortably above June's consumer price inflation rate of 2.6%. According to financial website Unbiased, the average Stocks and Shares ISA has delivered an annual total return of 9.64% over the last decade, with dividends reinvested. Why I think shares are betterOne investment I'm particularly pleased I bought is Scottish Mortgage Investment Trust (LSE: SMT).