Can sleeping with earplugs create risks such as not hearing smoke detectors and alarms?

Depends: If you can hear your alarm clock with your earplugs in, then i would assume you could hear the smoke detector which is usually louder. I suppose, to be absolutely safe, you could arrange for someone to set it off while you are sleeping.

Why earplugs?: Why do you wear earplugs? Do most sounds at night keep you awake? You could maybe get some type of smoke alarm with flashing lights if it is a concern. Maybe train your self to use a sound machine without using ear plugs.