Some car dealerships by me do this and "donate" police vehicles. You get the company branding, but (at least here) you can also gussy it up with extra boot licking nonsense. A municipality can't necessarily put a huge thin blue line paint job on an interceptor, but if it's a gift then can they really complain? Same with religious shit. Those same cruisers here have "one nation under god" on them as well. So you get a free christofascist oppression-mobile and even the public can't complain away the shit that's on it.

It's also implied that businesses gets preferential treatment. Pizza place gives the station free delivery a few times a week? No tickets. Car dealership gives a vehicle once every few years? No tickets. Cab company makes a ton of sense honestly.