Giving someone a ticket may not be an incentive, but getting someone's vehicle towed may be a satisfying experience for someone who just wants to kick some butt. Tickets aren't always reduced either.
Last, and most importantly, you have no recourse from having your vehicle impounded and your licence suspended. That's not the same as simply getting a ticket, even if that ticket may be considered an "abuse of power" (for example a ticket for 1km/h over the limit). That's nowhere close to that.
There's also the potential for kick-backs from a towing company, as seems to be the accusation in the Mahoney-Bruer case. When a law is created that bypasses the controls of The Court, the chance of abuse is that much greater.
Then there are the many cases that have been cited, in which HTA 172 was improperly applied to a lesser offence. Whether this is due to simple misunderstanding or strong-arming is immaterial to the accused, who has already been found guilty in a roadside trial.
I also think that OPP have been told to apply HTA 172 whenever possible, in order to simultaneously do two things; justify its existence and enforce The Commissioner's view of "the rule of law", by making people act as example. Fantino has a very 1930s view of police work. The man is an anachronism.