I had to record the vinyl to get usable digital files.
The reason it was backed off for the vinyl master is most likely due to physical limitations of the medium. If the audio channels are too loud (wide) there is risk that the needle will jump out of the groove.
You can see some examples of how dynamic range (they don’t track ‘mastering’ overall) varies across releases on this site: https://dr.loudness-war.info/
inability to encode very low tones.