Glass shower doors quickly build up hard water and soap scum. Unless you squeegee the door after each shower, it is difficult to remove all the build-up.
I put two products to the test to see which is easier And/or more effective. I tried Magic Eraser damp with a little Dawn on half the shower. On the other half I used Bar Keepers Friend, powdered version and a sponge with a scour safe pad on it.
As much as I believe Dawn is the most versatile cleaning product, in this circumstance Bar Keepers Friend was by far the easier AND most effective cleaner to eliminate soap scum And hard water from my shower door.
I would bet the liquid form of BKF would be even easier to use.