there're hundreds, even thousands of supercars in Dubai. and not every owner/driver is law-abidding citizen. so Dubai PD has to invest in top-end chasers, to takcle the problem of illigal racing. and if they've got budget, why not?
remember a few years ago London PD had to purchase 2 x NSX-R to chase illegal racing? word on street is, a lot people stop doing it now...if they're driving a car slower than NSX-R...
and a friend of mine once went flat-out with his WRX STi on highway in Johannesburg... and got pulled over by none other than E90 M3 (top speed restrictor turned off by BMW itself, obvisous) which JMPD just got the day before at slightly over 260Km/h... and he got lucky, coz the JMPD pulled him told him it's the first night he drove this car, so the officer gave him a ticket of 140km/h... that saved him thousands and jailtime