That's a good point. You will end up with histograms, that have very similar mathematical properties.
One reason to go with a custom implementation is user expectation.
You want your bins to start and end at human readable locations, so that the data can be interpreted more easily.
Inserting log(x) into a regular histogram is not going to give you that:
Taking the log of the data would add an extra computational step prior to recording the value I would think. Will need to think about that one a bit more.