The rule that the “best evidence must be given on which the nature of the case permits” [FN1] is an old rule has gone by the board long ago.  Underpinning that rule was an understanding that documentary proof is usually more reliable than human evidence.

It is now well established that any application of the best evidence rule is confined to cases in which it can be shown that the party has the original and could produce it but does not. [FN2]

The modern rule only requires that an original (which includes true copies or duplicate originals) should be tendered, if available. When an “original” document is unavailable, exceptionally, secondary evidence is admissible to prove the document. The court must be satisfied that an original document existed, but is unavailable: e.g. has been lost or destroyed, or is in the possession of a third party from whom production cannot be compelled.

R. v. Howe, 2017 NSSC 199, at para. 48.
The best evidence rule is not engaged when a document is not tendered as proof of its contents.
David Watt, Watt’s Manual of Criminal Evidence.

 [FN] Ford v Hopkins, 1 Salk. 283 (1701).
[FN2] R. v. Burton, 2017 NSSC 3 (CanLII), at para. 21: the term best evidence rule continues to be used even though what we are talking about is the documentary originals rule.