There are subtle sound differences between headphone cables, but generally their cost is greater than the amount of improvement (or change).
For example, someone could spend $300 on a cable... but would get more improvement by replacing their $200 DAC with a $500 DAC (even assuming best choices for all three).
I think that most of the Members of Trade here would agree with this.... except for the cable sellers.
Even if the improvement was just very slight in a boutique cable, that slight improvement stays with the headphone. Will you get that DAC's improvement in every peace of gear you plug your phones or every place you go with you phones?
Actually, I get double use from a DAC, because I use my DAC both for headphone listening and with speakers.
Whereas, I only use my top headphones (currently Alpha Dogs) there, and then use different headphones for portable use or elsewhere in the house.
So, such things certainly depend on each person's use.
I was just trying to point out that people should also consider benefit vs cost issue with cables. Most people who do have boutique cables, either a) have strong desires for cables that fit their comfort needs, or b) have $1k+ invested in each and every component in the chain, and so have hit "diminishing returns" on everything other than the cables.