Your internal flash will work without removing the HC-4A Hot Shoe Cover. The only time you'll take it off is to use an external flash, and high-tolerance machining ensures it won't slip out on its own.
In place, it protects the camera's flash contacts from rain and dirt, eliminates snagging when you pull the camera from your pocket, and it simply looks good.
Most market existing hot shoe covers don't support the pop-up flash function. In other words, while user inserts the hot shoe cover into the hot shoe socket, the build-in sensor will be turned off which causes the pop-up flash to be in no induction state. The special designed JJC HC-3 and HC-4 help users solve this problem.