The hearing before the Jewish authorities repeatedly mentions witnesses and their failure to agree. That concern is rooted in Israel's legal tradition rather than being an incidental courtroom detail.
A capital accusation could not properly rest upon the unsupported testimony of a single person.
Deuteronomy requires two or three witnesses to establish a matter involving serious punishment. It also condemns false testimony. In the Gospel hearing, witnesses are sought, but their accounts fail to provide the necessary agreement.
The narratives are not a complete transcript of every first-century judicial procedure, and later rabbinic legal codifications should not automatically be imposed on the scene. The biblical requirement for corroborating testimony, however, is directly relevant.
The background helps the reader understand why disagreement among witnesses matters. The problem is not merely that testimony sounds untidy; the reliability and concurrence of witnesses bear directly upon whether an accusation can be established.
The failed testimony contributes to the Gospel portrayal of the difficulty of substantiating a charge against Jesus even in a proceeding seeking grounds to condemn him.