I wonder if there is any advantage to a digital recording converted to say high quality aac, flac or whatever over ripping from a cd. Lots of my cds have very

I wonder if there is any advantage to a digital recording converted to say high quality aac, flac or whatever over ripping from a cd. Lots of my cds have very poor production on them. And on that note, how many recordings have been revisited? Can they improve them from re-masters, have they been, are they, or is that all a con to get you to buy them again?