I mean, it's a physical object, so you can map it. For example, if there was a path crossing it, then you would end up with a ford, which is a significant difference for navigation. For example, there are a lot of forest paths that seems usable, but are actually unbikable and even unwalkable because ditches/fords are not marked. For example, here is a ditch that wasn't drawn but a path was, but when actually surveying, it was a ford: https://www.mapillary.com/app/?pKey=795176745738722&focus=photo . If there had been water, it could have been impassable, which the map didn't show before. In any case, ditch networks are fairly important for stuff like flood predictions and whatnot. So there is definitely some value in it. Even though this tiny one is likely insignificant.