... Will a boresnake degrade accuracy or rifles integrity in any way ...
Well ... referring back to the primary question posed by the OP ... the answer is ... YES !
However ... let's qualify that response !
A basic engineering principle is that when two substances are in repetitive sliding contact with each other, the harder of the two is the one that shows more wear ! Thus virtually any pull or push through device in common usage will tend to "wear the barrel" assuming that the barrel is not made of the exclusive green cheese excavated from the surface of the Moon.
As an example I'd suggest you take a good look at the muzzle of a well-used WW1 British SMLE manufactured in 1914 or earlier ... or even one of the Remington-built P.14's of similar age. Those rifles were shot extensively ... and the cartridge primers were of the corrosive Berdan variety, requiring extensive - and prompt - cleaning after every usage period. They were cleaned, in the field, with the standard issue pull-though, which utilized a very soft cotton/hemp cord in its' construction.
Most muzzles of such rifles will show highly visible "flared-out grooves" in the bore that indicate the off-center direction of pulling by their owners. Of the ones still in my collection the grooves are very obvious.
BUT ... fear not ... it is highly doubtful that any of you will ever perform the cleaning operation with the frequency or intensity - or in such a wet, muddy environment - as the rifles mentioned above !
Fuzzy