[bornmiddleaged]

This would really annoy me. I think it's not fit for purpose on an automatic as it kicks in as you pull up to a roundabout, for example, where you often need to be able to pull away quickly and not have to wait for the engine to restart.
OK, I admit it is very quick to restart the engine, but there is still a discernible pause.
In a manual, you can keep the clutch dipped which will stop the start/stop from engaging.

Not sure if you have this on the XC40 but on the V60 you can choose an Individual driving mode and one of the options in setting that up is whether to have start/stop enabled. So you could have an individual mode that still used the "comfort" engine mode but with S/S disabled.
But you have to choose that mode manually every time you start the car.
Does the XC40 have the drive mode select button by the gearstick?