Speaker cable geometry question


First of all, I'm sure this has been asked somewhere but I couldn't find it.  I have been out of the loop for a while and have just gotten back into the hobby and am looking for an answer on this (because I am just curious).  
Most speaker cables consist of any number of geometries in a single run from amp to each speaker in a single sheath.    Some however have single runs of + and - to each speaker.  Such examples include certain Purist cables such as Dominus and Neptune, Jena Labs and Nordost.  I am sure there are more but these are the ones that came to mind.
What is the advantage or disadvantage of doing a cable run in this manner.  These are very expensive brands and I've been rekindling my interest and this is one area in which I have developed a particular curiosity. 
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Spacing wires apart will obviously reduce wire-to-wire capacitance with some increase of the wire inductance (that is more important IMHO).  In addition electrical noise pickup is proportional to the area between wires.  It might not  seem important (since it is output), but output, in most cases in an input to NFB.  There is no right or wrong here.  It all depends on your system, your location etc.
+1 what Kijanki said

https://www.st-andrews.ac.uk/~www_pa/Scots_Guide/audio/skineffect/page5.html

nutella, I can't add any additional comments as kijanki and shadorne's comments are spot on.
If you should be in the market for speaker cables I would most highly recommend you take a look at the Cerious Technologies Graphene speaker cables, huge giant killers at a very fair price, and a fraction of the cost as the speaker cables you mentioned.
Thanks Shadorne, I've read stuff like that basically and on this page in particular, Fig 11 shows no more than a 0.025 dB drop at 25 kHz for the largest spacing of that particular example.  Fig 13 shows with the largest wire a difference of around 0.01 dB for increasing the wire spacing from 9mm to 12mm.  And figure 14 shows a differnce of 50 nanoseconds (0.000000005 seconds).  Further it comments that " In practice it is questionable whether delays of the magnitudes shown would ever be audible. "

Now, as an example, Nordost Tyr has 26 conductors of 22awg for a total of approx  8 awg wire.  Jena has some of variation on this type of geometry as well in separate + and - runs.  Not sure what's inside separate Purist audio runs but wonder what if any advantage or disadvantage using separate + and - is apparent or even perceptible.