[mylesdw]

Mr Fixit is right, no engine needs vacuum advance, that is why race cars run without it.

For road use however, where most of the time is spend at part throttle rather than WOT there a significant benefits to fuel economy and clean burning. If the car has to pass an emissions check where they check unburnt hydrocarbons with the engine running at no load, a bit of extra advance will help.

There are no disadvantages to running vacuum advance.