Actually, the Motif XS does have styles. They have programs where when you press chords, it would follow your chord changes just like a “traditional” arranger.
When you press the SF buttons, you can get variations and fills.

Now, it has its limitations. For example, it only has four (4) tracks and not 8 like “traditional” arrangers.
And, the fills don’t behaves like a “traditional” does in that if a style has four beats per bar, you can not press fill on the second beat and have the fill last for 2 beats. The fill will last for 4 beats.

But all of that is just operational features that can and probably will be corrected by an upgrade.

It is very easy to use the Motif XS as an arranger. For example, some one could use the motif XS to play Misty. The accompany section could have drums, bass and a guitar and the melody could be played with a piano.
If some one did that and put it up as a demo and not tell you what keyboard they were using, you would think it was an arranger played with a very simple style.