I am Eb1 EA applicant. and I really doudt that this is even possible. Like no other category Eb1 is a very personalized, very very detailed and almost exclusive category. There is no way both can be approved. You have to see which requirements cover your bases the best.
The reason it is rare is because applicants from visa retrogressed countries has nothing else to gain in terms of priority date. The requirements for EB1-OR is simpler (as it requires you to satisfy fewer criterias) but requires the petition to be submitted by an employer.
It has nothing to do with "very very detailed requirements". If the goal is to speed up processing (assuming one category is taking longer to adjudicate), then it makes sense to submit EB1-OR and EB1-EA.