I'm curious about what makes the eye piece a requirement for these particular photographers (and if/how it could be done away with).
You are shooting with a long lens. Unless you have the camera on a tripod/monopod, it’s much more stable to have the camera braced against your body with the viewfinder up against your eye, versus trying to hold 5 pounds of very long lens at arm’s length.
(Nikon 200–500mm lens in this case. Trust me. Way easier to support that chonker when it’s held close to the body when running around to shoot rugby.)
Her eyesight has changed, the focus correction on the eye piece is not working well for her now (it has limited correction range) and her glasses are in the way. Using the back screen is difficult outside because of the sun and speed. Also strength; holding a camera with a big lens at arm's length all day is hard for her.
So - contacts, which she hates and her eyes react badly to.
She might have to pack up, which would be very upsetting for her having built a business and because she get's a lot out of her work.
The alternatives in strong sunlight would be a rigid hood around the screen (which exist as accessories), or a fabric hood covering the screen and photographer (like what early photographers used).
And possibly easier aiming/coordination/stability with the camera and hands at not just eye-level, but also nearly right up against the eye, moving in unison with one’s head. Just a guess though. Sports television cameramen seem to do just find tracking the ball without using a viewfinder.
When you hold up a camera to your eye and use the viewfinder - it’s a third point of contact. You’re also using your face to stabilize it.
Trust me - they’d get rid of the damn viewfinder if it wasn’t often requested so much. Using the viewfinder is just a lot easier than the back of the screen in many situations. (Especially outdoors. Think about rain or whatever else going on getting on the screen)