The Big Bang is a very slow moving projectile that can absorb lots of enemy projectile hits.
So while you might not be able to quickly punish enemies from afar,
its absorbing nature makes it act like a moving wall of death, though the opponent can jump over it.
Also, you can keep charging the move for as long as you'd desire, making the Big Bang sphere grow in size up to four times.
For about 2 seconds after Vegeta launches the Big Bang, you can input the RDP+P command to have him manually detonate the sphere.
In later updates to Majin Vegeta the Big Bang was recoded to start out as a LV1 move but with the player able to charge it up by
gradually draining any remaining power bar you currently have left,
with a full power bar even able to boost it up to a LV3 move.