How useful is a PhD in computer science and/or machine learning these days?

Its useful to have phd because of the research methodology discipline and the classes you have to take to learn Statistics for the final thesis. Having a PhD in computer science almost means you do know how to code with one language, which is definitely helpful when you are building your model in R or Python. Also the fact that you have a broader knowledge in the domain (ideally), gives you the credential to create a defensible model.