In
episode 5, Beerus acknowledges Goku is holding back his "
hidden power" and demands he display "
everything" and unleash "[his]
real power", and Goku describes Super Saiyan 3 as the "
most powerful [of the Super Saiyan forms]"; after Goku instinctively evades Beerus's killing blow, Beerus even wonders if Goku is "
hiding more powers". By the end of
Daima, as an adult, Goku could freely use the full extents of the power of Super Saiyan 4, which is
vastly superior to the previous form. He has
zero reason to not use Super Saiyan 4, which presumably yields a far more stable energy consumption, when asked to display
everything he has.