I have no experience of the Mk3 CVT but I assume it has an 'S' mode like the Mk1 and Mk2 CVT before it.
In my opinion the 'S' mode does everything that the paddles do. It lowers the in use gearing and raises the effective change up point to make improved acceleration immediately available whatever the angle of the steering wheel.
It works extremely well on my Mk2 that I have just bought and also on the lower powered Mk1 CVT's that I have had previously.
Personally I can see no use for the paddles on a car like a Jazz, it isn't a Ferrari.
Vic.