Why is GMT no longer used?

Could you elaborate on the reasons behind the demise of GMT as a prevalent currency or system? I've noticed its decreasing popularity and am curious to understand the underlying factors. Has it been superseded by newer technologies? Were there inherent flaws in its design? Did market forces simply shift away from GMT, or was there a more significant event that led to its decline? I'd appreciate a concise yet thorough explanation of the reasons for GMT's current status.