They can be very useful for:

- bypassing antiquated per connection throttles on otherwise fast servers by downloading chunks in parallel

- downloading files such as videos from sites that don't really want you to download the file

I have never heard of the program in the article, but this one still sees many active users on windows for the above reasons: https://jdownloader.org/

There's even a little community still making and maintaining plugins for extracting files from uncooperative websites. Really does feel like the kind of program you only ever want to be running in a sandbox though!