When cars were just being invented... most of them had Starter/Generators on them.... if the engine were turning it it produced electricity...and if you fed power to it it was an electric motor....
As such it was attached and geared in a fashion which would actually take advantage of braking by using the engine much more directly than this add on..
And would have worked much better on a Diesel since they completely cut of fuel when being used for a brake... unlike carbed gas engines which will draw gas in just due to air flow. ( talking historically here )...
Just a few decades ago Gravely Two wheeled walking tractors still used this generator/starter combo on the 8 and 10 hp models.... and plenty of them are still in use...