Why is it faster to restore applications from System Tray than from the Taskbar?
When you click on the taskbar icon, the application first has to start and then checks, if another process of the program is running. If so, it puts the process in the foreground and terminates itself.
But when clicking on the small system tray icon, you already have an associated process, which will then get put in the foreground. No application or program tries to start in this case.