If South Korea adds a number (the specific number is too long to remember), it will be charged by the second, which is equivalent to about 0.33 yuan per minute, which is not much more expensive than domestic long-distance calls.
In addition, QQ WeChat can be accessed anywhere with network and equipment, and we often use QQ to contact our domestic friends there, so we can use it with confidence. We don't use MSN because we are not used to it, not because we can't use it. QQ is the same.