But what's more important? small files or large?
Very large files will be rare, otherwise you would run out of space. Very small files may be very important, but even a large number of them will not take up much space. Most space will be devoted to something in between ... but where is the bulk of storage devoted?
The (mental) challenge is to determine how file size is distributed, given some starting directory. My opinion is that exponential categories are appropriate, that is, 10..99 bytes, 100..999 bytes, 1000..9999 bytes, etc. Categorizing and formatting is a personal choice, determined in part by what is convenient, so long as useful information is displayed.