The eyepiece cover has nothing to do with metering, it's that with long exposures, you sometimes have light leak THROUGH THE VIEWFINDER so you need to cover it so that when the mirror is up and shutter is open, the film doesn't get unwanted stray light from the viewfinder.
As said here, the cover definitely has everything to do with metering. Except on a camera like the LX, which has no blind and does not need the eyepiece covered, because stray light through the eyepiece does not reach the photocell. I had to point a flashlight directly into the eyepiece to affect the meter reading on mine, and even then it went up only one stop. As for viewfinder stray light reaching the film with the mirror up and shutter open, it will never happen unless the light seals are bad. Otherwise, no one could ever use a waist level finder or sports finder.
I do use a digital device in my photographic pursuits when necessary.
When someone rags on me for using film, I use a middle digit, upraised.