|A scratch IS physical damage. If you can see it, feel it, touch it...etc then it is physical.|
Yes... the recover SKIPS what it can not read and therefore you end up with an incomplete disk.
Things like cassette tape can have lost information but still play. DVD's are not like that. If some of the information is missing then more often than not it effects the playback of the ENTIRE disk.
A cassette tape blindly gets pulled over the heads reading information that is there. If there is none then the tape continues to get pulled until information is found.
DVD players on the other hand LOOK AHEAD for certain pieces of info. If that info is not there then the dvd player doesn't know what to do next.