Yu Xi will be able to reap more life value from those designated target of hers each time she kisses every one of them, even if just for a brief period of time.
It was also for this reason that the system had strongly advised her not to let go of any of the designated targets so easily since doing so would drastically diminish the life energy and the life value acquired with each action (every kiss) delivered to them.
Yu Xi: However, it has become quite an exhausting activity for me to try to obtain life energy from these designated targets of mine.