Protein can be converted to glucose by a process called gluconeogenisis. The percent of protein converted is small, I understand in the low teens for meat, eggs etc.. It is slow process and it should be borne in mind that not all of a food item is protein so the actual quantity of protein turned to glucose is small. In my opinion it can usually be happily ignored.
The body is a fascinating mechanism and has the ability to produce glucose and other chemicals it requires from many unlikely sources. If you are eating carbs most of the glucose you use will come from the carbs. If you are very low or no carb then it is possible to go into ketosis and use body fat to produce the ketones which the body uses instead of glucose.
Protein is needed for healthy muscles, it is used to repair and grow them. It is needed because damage occurs to muscles in use and the repair/replacement of cells is a continuous process.
Cheese and eggs contain far more fat than protein which provides a feeling of satiety so you feel full longer. You also need fats to provide fuel for other bodily mechanisms and here I get hazy at the moment so will leave it at that.
Hope that helps and that someone with better understanding will be along to expand and/or correct anything that needs it.