It depends on how much time you have on your hands.
Oracle Linux is a Red Hat Enterprise Linux clone. Almost everything in an Oracle cert would apply to RHEL.
If that is useful knowledge for you, consider doing it. Then be sure to okay with RHEL to apply what you learned. Knowing RHEL is much more commercially useful than knowing Oracle Linux. RHEL is probably still the most important distro to be familiar with commercially. Oracle Linux, Rocky, Alma, and other are RHEL clones and many places use those.
If these skills are not useful for your job, or if you do not have the time to waste studying it, then do something more valuable.
The skills are useful. I will let others chime in with opinions on how valuable the certification itself is. Maybe not much.
We do not have to buy it