Two different things here:
1) Oracle Certified Professional
A little experience and some exam cramming and most DBA's will be able to pass it. It's sad that people do it this way, but that's the way of the world. I still think it's good to do for reasons here
https://connormcdonald.wordpress.com/2016/01/20/certification-exams/ 2) Oracle Certified Master
Is a different beast altogether. Practical, tough, real life assessment criteria. Anyone that is an OCM I believe would always be asset to an organization.
But yes...it aint cheap.