Is videotaping confessions a good idea?
I would argue that it is not.
Of course, videotaped confessions sound good because they can protect both the accused and the police. They can make it clear (it seems) whether the statement was coerced or in some way done unproperly.
On the other hand, videotaped confessions come with major problems. For law enforcement, they are a major financial burden because of the need for equipment. They also make it so confessions can only be taken in places that have recording facilities. On the side of the accused, videotapes give more credibility to confessions even if they have been coerced in some way. The police can put all sorts of pressure on the accused, then put him in front of the camera. All the jury will see is the part on camera, which will seem even more compelling than confessions already do.
A more appropriate question would be "Is videotaping all interchanges with police and suspects a good idea?" Most police departments can now stream the arrest back to the station (or whereever the storage is, cloud or whatever), many police cars have their own camera system, and jails routinely record. By requiring that all interrogations be recorded, it lessens the chance of cooercion. This is especially true with younger people who have been arrested, who may not know their rights and who are more easily pressured. There is plenty of empirical evidence that false confessions also go down when interrogations are recorded.