Oil pressure is the oil your engine CAN NOT USE at that time
10psi oil pressure means your engine can't use all the oil the pump is providing, and its backing up in the main passage with 10psi pressure
The oil has to squeeze out of bearings and lifters and oil passages and only so much oil can do that at any given RPM and oil viscosity
No oil pressure would mean pumps not supplying enough oil
Above 60psi would be too much pressure in most engines, and you can get "washing" at the bearings, the oil PRESSURE is high enough so that it pressure washes bearing surfaces so no oil and they get real hot real fast and fail
Generally speaking stock oil pump will provide 10psi at 1,000RPM, 20psi at 2,000RPM, 30psi at 3,000RPM, and usually top out at 45psi
So more than enough flow since engine is using much less oil flow at 3,000rpm since pressure is now 30psi