Well, the "size of the ruler" you choose can produce a substantial change in the accumulated vertical gain. So I guess that makes it worth paying attention to.

To keep from recording "silly small" undulations in elevation, devices use a low-pass filter that ignores changes below a certain amount. This filters out small variations due to sensor errors and very small uphills like freeway overpasses.

The de facto standard filter seems to be about 10 meters. If I recall correctly, that was what the Avocet 50 (the mother of all elevation recording bike computers) was set to.

Many arguments ensued over what the "proper" filter size should be, but 10 meters seems to have survived the assaults.