Ghee is clarified butter, the medical establishment urges us to reduce the amount of animal fats we consume and replace with vegetable oil. To some extent I would go along with this as long as it isn't detrimental to the taste of food.
In India, and other Asian countries, vegetable ghee is available, this tends to be made from hydrogenated vegetable fat and will contain trans fats, so leave it alone.
Olive oil will be better, health wise, than vegetable ghee and is also probably better health wise than cow ghee for the long term diet. Use liquid olive or other liquid vegetable oils for daily cooking purposes and just use cow ghee for special treats and celebrations, and for anything where liquid vegetable oils don't give the right result.