Not every metal part requires the 0.001" tolerance you can get with CNC as well.
I look at it as another technology that can be selected when the parameters make sense for it. I'm more familiar with plastic technologies, for them I switch between FDM, SLS, SLA, Polyjet and Injection Molding depending on:
- Forecasted quantity
- Time to market needed
- Price constraints
- Accuracy and surface finish required
- Design requirements
Each technology has it's own advantages and disadvantages.
Make a lot of parts on a printer and you spend a little more time designing the part and time to tune the settings (which might be done depending on the material you use) and you're off and printing and just paying for print time. Not cheap, but cheaper than paying techs at mid-scale.