OK...let's see if the XS is has arranger functions ...AND we all know it's a bunch cheaper that a T3..and you can get them in 61, 76 & 88...why, then do we buy a REAL arranger..the T3??
Do you suppose it's for the fantastic VP, NOT, how about the superb full arranger function, into's, vars endigs ect CONTENY and available content...Yep!

A Motif, Fantom, PC3 etc. can make some great music in the hands of a very talented PRO player...arrangers are for the most part home keyboards, also..used some for song writing, and pofessional entertaiment (Paid)

Terminology does not change what it will and will not do....That said..my Kurzweil K600X (and a PC3 for a while)can play sequences, ARPs etc and sounds real good...but it is not an arranger as MOST of us would describe it!

From what I have observed..the main utilization of most WS's is to go on stage, play along with all the much louder instruments, especially guitars screeming, to be part of the group.
Beautiful instruments and talented keyboard players..that you rarly can even hear. Exceptions of course...like the Bee Gees etc.
And of course studio work.

Of course some of us have both so we can use the right tool for the job.

Lee S.