Your solution only fits for CD source only, CD is best to play from CDP. But what about rest? When I want to buy and play online hd files or want to upgrade youtube sound or TV STB or other online source then a nice quality DAC is must. For convenience or versatility now a day DAC is must have component.
Then ofcourse you need a DAC.No contest there. My personal opinion was only for CD players playing Redbook or SACD.