IMO no.
They will soon gather carbon again once the engine is fired up, but having cleaned them, this will stop that build up from accumulating into something detrimental to performance.
I would say that cleaning the ring channels is the most important aspect, if the rings stick in the piston, they become ineffective and of course by allowing compression to pass into the crank case, this leads to excessive emissions from the breather, a smelly engine, poor performance, oil consumption and everything nasty that lesser vehicles (mentioning no names of course) suffer from!