[stumped]

I still don't get the value, sorry - for every 100 fiction books i buy - i might consider re-reading 1 out of the 100
knowing that some of the other 99 have been updated but not knowing how - they fix a comma or add delete a paragraph, or correct one or more typos - seems to be useless information ?

if I were buying educational reference tomes than I could see the value - but read-once mystery/thriller/novels - no.

I accept they will only auto update on the device orignally sent to but as they don't divulge what device that was ?, is'a a crap service. many of my book went to a " wrong" device as there was some default that I did not get around to changing & because I suspect that every time you buy a new device that auto-becomes your default send-to device for everything
mostly amazon are very good but when they are bad they are shockingly bad. e.g. ( off topic) i know I can only uploaded 250 of my own songs fro free to amazon music. but it is impossible to see how many of the 250 slots i had used , and i had to go thru 3 x CS people before i got to one who understood the question . the music app used to say thet, then they updated it to a version that does not say.. as for getting a list of the 235 songs that amazon say I have uploaded, well I gave up on that after wasting about 2 hours on the web site and in the music app options