Why not? I have no concerns about a third party scoring my driving style. The insurance was also far cheaper than the alternatives offered, as I do not have any NCD to apply to this car, as I am retaining my old car.
Also, I get to try the whole thing for free, as I can cancel during the cooling-off period for free if the scores do look bad. Also, as noted by others, I can cancel if the scoring system decides that it does not like me before Hastings can cancel at their end.
Don't forget it is a modern car, in terms of tracking data, it has a built-in sim that means certain aspects of my driving are recorded by the mobile phone network. At the same time, I have my own phone and a dash cam fitted. If the police were to get involved with any accident I was involved in, they have access to a lot of data about my driving, and that is before other drivers offer up their dash-cam footage.