[nyconyco]

It is worse, actually, because it uses GTK, and is only available on Linux and Windows (not macOS, although there have been attempts).

Most of the "big names" who provide modern and contemporary desktop IM apps deliver on the 3 platforms (Linux, macOS, and Windows), and use mostly web "technologies" (sometimes "pure browser", and sometimes with electron-like desktop "packaging")... so as a consequence, it is very native, indeed, but it is a generally consistent and continuous UX (user experience) between mobile/tablet and desktop/laptop.