Workstations:

Have performances, Combinations or whatever the manufacturer calls them. They are much simpler in instrumentation than Styles. They do not have intros, fills, variations and endings. Motif lets you vary the arps. Korg has Karma which provides variations.

If you want to sit down and quickly start playing with an accompaniment you can do it with both. However you will find that the workstation will be heavily oriented toward modern backing tracks. Plus the number of performances/Combis are limited so you will need to make your own and that's where the workstations require a steep learning curve and a lot of work. The upside is you can create very original tracks.

With Arrangers creating new styles is a lot easier to do than using workstations to create new performances/Combis.

Summary:

Arrangers have many styles that can be changed and with their OS it is easier to create new ones. Styles cover a wide variety of generes.

Workstations have a limited number of performances/Combis. They can be changed fairly easily, however it takes a lot of learning and work to know how to create new ones and even more work to create style-like backing tracks with intros, variations and endings. Plus backing tracks are oriented to more modern accompaniment.

In the end you can accomplish the same objective with both but the workstation requires more work. That's why TOTL arrangers cost less than TOTL workstations.

I still would like to add a Motif or MOX to my Tyros 3 for the different sound world it would bring.