I was recommended to take vit k2 as I previously had kidney stones (removed) opinions? And why so?

Calcium "director" While vit k is important in blood coagulation, vit k2 (menaquinone) is important in channeling calcium to bone to prevent osteoporosis, and in doing so, decreases available calcium from entering the urine. Should probably betaken in conjunction with vit d2/3 and daily exercise.
Kidney stones; vit K. See also dr. Chinn's answer re vit k2. If your stones are calcium oxalate (most common type), pts are often advised to take a citrate supplement (potassium [k] citrate, calcium [ca] citrate, or magnesium [mg] citrate) to block the formation of stones. It is also critically important for pts to drink plenty of water (1-3 liters) every day to keep urine dilute ; prevent stones from forming.