It also says “free of installer bundles” while (at least in past, don’t know about now) their default windows installer was including ads (source)
P.S.: If you want to disable the in-app ads, here’s how to: https://gist.github.com/yunooooo/87564a0293a1c7a53fb3e233a604c638
More like JDownloader supports almost every download host website in existence without any hoops. Most other applications just support standard http downloads which may be difficult to use with many websites.