What can they do that the windows explorer file manager can't ?
Like Directory Opus for example.
I used Directory Opus 4 on the Amiga. It was handy for providing capabilities for file management that were unlikely to be found in an 80s/early 90s operating system GUI, but Windows has most of the capabilities I need these days. If I were so inclined I might introduce a 'command prompt here' add-on into explorer and something that provides WinDirStat's capabilities but through a right-click action, but I can't think of anything major that would be useful in the way of having a separate file management program.
The other thing is that my line of work mostly involves working on other peoples' computers, so a toolkit that doesn't need to be installed is more useful to me. On my home computer, my files are reasonably well organised, and I write scripts to do things like prepare files for certain types of backups I do.