Yep, this is a known fact.
Of lately people seem to like the Sonic CD way of things.
Quote from Mercury, SFR programmer:
Let's see what the instruction manual says about this move:
It is some kind of "super stunt". That's all I can find. maybe the Japanese manual has more information (that would be in Japanese so I can't understand it).
Now, let's look at the games which use this move:
Sonic 1, Sonic 2, Sonic 3, Sonic & Knuckles, Knuckles in Sonic 2, Sonic Advance 1, Sonic Advance 2, Sonic Advance 3. (possibly more?)
That is an impressive collection of games using this move, so there must be a reason behind it. I have certainly missed it if it was uncovered before.
The only thing I could think of is that such a move could be used as a game feature to get more score points while attacking enemies (since it is more difficult to aim, it should be rewarded if succeeded). But I haven't found any traces leading to this. Also the Sonic Advance series don't abort the move when activating the quick shield (like Sonic 3 does), yet again to prove the move is not a leftover but very much an active game feature.
Now I am asking Sonic Retro to find the answer. Old interviews, new interviews, hacking, testing, anything that can uncover why the move is still such deeply tied to the original Sonic games.