Question about Jamo S426

I have the speakers and a receiver and that's enough for me. I don't know what the advantage of an additional subwoofer is. Quote from the description of the speakers, pay attention to the last two words: "Instead of offering a small sub/sat system, Jamo goes the other way and adds two S426 floorstanding speakers to the set. These two-way bass reflex speakers come with two 140 mm bass drivers and, thanks to high efficiency, make an active subwoofer unnecessary."
Greetings, Marco

A matter of taste. I think: Yes!

For me, a subwoofer is necessary to "round off" the whole sound picture.
I want to hear all sounds, even those that are so low that "normal" speakers cannot reproduce them at all.
(depending on the music or film, you miss out on a lot if you don't have a sub...)
Music where bass is important and movies will definitely benefit from it.