I'm a person who starts sweating easily, so there's a high chance I'd feel at least some discomfort after. On the other hand, if the exercise is mild enough not to make me sweat, it's probably next to useless for me.
I don't think you're supposed to get fit, the benefit is more that it stops you sitting in your chair for 8 hours straight.
They should invest in standing desks, then.
Nah. I think the real benefit is that they have a "victory" every few hours to keep them going.