I would suggest that Montage would be a more preferable choice as for Mozart, because he's more of a soundtrack kind of musician, as well as for Beatles, since they are a band kind of musicians. It seems possible that songwriters like Sting or Elton John may be tempted to get one, the question is whether they are still interested in having it all or got focused on an essential, yet perfected minimum.
Speaking about Russian popular artists, I can see in magazines that they have Tyros or Clavinova-version of Tyros at their houses.
I guess that the term "workstation" had more meaning in those days when computers were not so popular and portable and it was essential that the keyboard allowed you to produce the whole song inside. I remember there even was a keyboard which could burn CD's.
As I see it, Yamaha calls PSR-S670 and above as workstations to underline a class difference between S- and E- series.