I'm a TDS CM and bought my last add-on the day that my rehire became effective. Just called up my guide and booked it right then.
And since I bought 100 points, I got the 15% off and then the $10pp off after that. Sweet. A very nice benefit for four months of work.
As far as WDW CMs owning, I know my guide owns at HH, but she wants to get away from FL and she said that she trades a lot too. Maybe they buy to trade?
Another reason may be what I'm thinking of doing - when we retire or semi-retire and move near WDW, then we will have a much smaller place. Having the points will allow our family to come visit without having to stay with us.
Also sweet.