why cannon on aircraft are so inaccurate ?

all aircraft have gun computing systems , all engage very slow target (just human or truck that either stationary or moving very slow ) , from relatively slow aircraft but gun video always shown that bullet seem to fly all over the place (like 10-15 meter from target ) ? not accurate at all ,why is that ?
A-10 Warthog Gun Runs
https://www.youtube.com/watch?v=WAnFr0VXFYI
Apache kills Taliban
https://www.youtube.com/watch?v=KTVeve_CtzE
Tiger Helicopter Smashes Taliban
https://www.youtube.com/watch?v=1Wp8_AeH6hE
Apache Gunship
https://www.youtube.com/watch?v=q7d2Pe67brQ

another question people said system such as Kashtan CIWS was designed to have very high dispense thus have higher chance of intercepting target due to more area cover , how accurate is that claim ? (would it better or worse for a cannon to be accurate ?)
https://www.youtube.com/watch?v=ELgua-Slx2o