Quote from Opium:
Seems weird that anyone would record the actual time when the game time is all that really matters.
On the contrary, game time matters absolutely not at all in the most common form of speed running Super Metroid, racing. There have been many instances where one person with a higher game time beat someone with a lower game time, sometimes by as much as half a minute.
Thus, the importance of the real time measurement. Very few of the current runners actually care about game time.