the first is just some kind of Spotlight clone
Kind of. Its main benefit is to integrate into the standard OS file dialogs to quickly change folder. For instance, the app alway sets file open to ~/appdata/app/user or similar, whereas I've just saved (from another app) to r:/temp. One click change. Of course, there are favourites, searching and all that stuff, but they are not the primary use.
It's greatest feature, that I use a
lot, is to use some other file explorer app/dialog. For instance, you choose file save and the app opens up the last folder it saved to (say, ~/long path/project1). But you in DOpus you have open ~/long other path/project20. No problem, Listary will instantly change the file save dialog to the project20 path. You don't realise how useful this is until you use it (kind of like mouse wheels and back buttons).
the second is roughly an enhanced Midnight Commander
You could say Midnight Commander is roughly an enhanced Explorer. There is much more to it than that. Much more.
and the 3rd backup
Which shows you don't realise what you're missing. Yes, it's a backup (and restore - don't forget that). But it write images. And significantly it can do that on a live system - this uses Windows shadow service, but there are similar that use their own variation of same. There are none that can do that on Linux - if you have open files you can't back them up.
Further, it does incremental and differential images. Significantly, it knows which main a diff or inc comes from. That is, you can do a main on media1 and a main on media2, then diff on media1, another diff on media1, then a diff on media2. The diff on media2 will be correct and completely unaffected by whatever is on media1. And a further diff on media1 will be unaffected by whatever is on media2. Ditto for incs, of course.
Result is that you can have multiple coherent backups, utilising differential and incremental stategies, completely independent of, and unaffected by, each other. And do that without having to pop off for a coffee while it happens.