Goku using Instant Transmission Against Birusu?

[ドラゴ]

According to what I know about IT, it's used to travel long distances usually accompanied by the user placing his index and middle fingers on his forehead to help him concentrate, though if extra time is taken the technique can be performed without this aid. However, when Goku was fightng Birusu, he used his index fingers in short bursts to tackle Birusu's speed or maybe, from what I could see, Birusu wasn't moving that fast and Goku looked asif he was creating space to counter Birusu's advance on him.

What would the difference be to using the After Image or Zanzoken technique frequently used in fights? Unless, they're implying Birusu was fighting at instantaneous combat speeds, still doesn't explain why Goku used IT during a close-quarter fight. If you watch Movie 6 - The Return of Cooler, theres a short melee composed of instant transmission fighting between Goku and Cooler up close and personal, with no extended finger use.

[Darknat]

According to what I know about IT, it's used to travel long distances usually accompanied by the user placing his index and middle fingers on his forehead to help him concentrate, though if extra time is taken the technique can be performed without this aid. However, when Goku was fightng Birusu, he used his index fingers in short bursts to tackle Birusu's speed or maybe, from what I could see, Birusu wasn't moving that fast and Goku looked asif he was creating space to counter Birusu's advance on him.

What would the difference be to using the After Image or Zanzoken technique frequently used in fights? Unless, they're implying Birusu was fighting at instantaneous combat speeds, still doesn't explain why Goku used IT during a close-quarter fight. If you watch Movie 6 - The Return of Cooler, theres a short melee composed of instant transmission fighting between Goku and Cooler up close and personal, with no extended finger use.

Zanzouken depends on the speed of the character whereas instant transmission is... instant. If you take in consideration movie 6 and movie 8 it seems there is some kind of distorted space where time do pass when using this technique, but time doesn't seem to pass in the normal world when using it, so in theory if people use the instant transmission during a combat they can struggle in this sort of dimension (again, taking in consideration the movies, in the manga it's just instantaneous).

I haven't seen Battle of Gods, but i suppose Birusu was way faster than Goku, and using instant transmission he could even the gap in speeds.

[GTx10]

I always thought IT wasn't detected by folks who can sense Ki. Unless I'm wrong. If Ki can be felt by a IT user it begs the question why Beers didn't know Goku's moves ahead of time.