Recently, I am doing the battery charger by using the flyback.

and I am curious about one thing, the flyback can works in CCM mode and DCM mode,

  but most battery charger systems using DCM flyback, I know the DCM flyback can do the valley ZVS.

Is this the reason to design the flyback in DCM? any else?

Recently, I have been working on a battery charger design based on a flyback DC-DC converter and I am curious about one thing: the flyback converter can work in CCM (continuous conduction mode) and DCM (discontinous conduction mode), but most battery charger systems use a flyback set up for DCM and I know the DCM flyback converter can use the valley ZVS.

Is this the reason for ensuring that the flyback converter works in DCM (the valley ZVS)? Is there anything else that could motivate this?