Renaming a file works well when there is just one. But when you have a directory full of them it gets tedious quickly.
With nametrans you can use search and replace on your list of files as you would on text in a document.
And with regular expressions you have even more power to transform file names (and whole file paths) systematically.
With useful presets for common fixes like lowercasing or capitalization you can keep your filenames nice and tidy, whether 10 or 10,000 of them, in one go.