The script would indicate that their plan is to "avoid flak", presumably by making their path extremely hard to track and predict. That would explain their formation flying, heading through clouds of debris and constant desire to stick close to larger objects.
PAN DOWN to reveal a REPUBLIC ATTACK CRUISER. Continue to PAN with the Cruiser as TWO JEDI STARFIGHTERS enter and head toward an enemy Battle Cruiser. TRUCK with the Jedi Fighters as they maneuver in unison, dodging flack and enemy laser fire. R2-D2 is on Anakin's ship. R4-P17 is on Obi-Wan's ship. A giant space battle is revealed as the tiny Jedi ships continue their assault in a synchronous ballet.
2 INT. OBI-WAN'S STARFIGHTER COCKPIT-SPACE
OBI-WAN bounces through the flack with a frown. His ship rocks violently.
The cruiser dropped away behind them. Out in open space, he was a
sitting duck. He needed something else to dodge behind. A Separatist
battleship loomed — not the best idea, perhaps, but the only one
available at the moment. “I’m going down on the deck,” he told Anakin.
He swung his fighter, narrowly avoiding another barrage of laser fire.
Revenge of the Sith: Official Junior Novelisation
It's always worth pointing out that a Jedi's actions, no matter how seemingly unneeded are guided by the Force to find them the best route to their goal. In this case that apparently required spinning and whirling like idiots.
New bursts of flak bracketed his path. He reached into the Force,
feeling for a safe channel through the swarms of shrapnel and sizzling
nets of particle beams.
There wasn’t one.
Revenge of the Sith: Official Novelisation