The effective range of an SVD with subsonic ammo is actually quite short because of the steep trajectory of subsonic ammo and there is no subsonic ammo for the SVD in the 700 grain bullet weight range, so really you can't compare.
A better comparison would be a 9 x 39mm calibre weapon like the various 9 x 39mm suppressed weapons like the VSS and even SR-3.
Even they can't compete with the VKS and they are not supposed to.
The VSK is a long range suppressed weapon for use against targets wearing body armour.
Obviously some types of body armour will stop its round, but even someone rugged up for close combat will have exposed bits... a 50 cal solid bronze slug through the pelvis will slow anyone down if you know what I mean.
Either way I am happy to drop this... it was only an off the cuff comment... but to answer your question directly... this weapon is specifically designed with a custom designed round for the job.
It makes sense that if you are issued this weapon your job is to kill at a distance, quietly, and most likely either through a structure like a wall or through personal body armour.
Ammunition should not be a problem because there is only sniper ammo for this weapon because it is unique. There are no standard assault rifle rounds or machine gun rounds because the only weapon in this calibre is a sniper round so the only round available are sniper rounds.
The example you gave showed a general shortage of specialist sniper rounds in a calibre very widely used in the conflict by machine guns. One suspects that sniper ammo was sent everywhere machine gun ammo was sent and in some places where snipers were not widely used there were probably great stacks of boxes of the stuff just sitting there with no one asking for it. Sort thing any bureaucracy can do and will do.