…the person has disappeared, and joined the great single existence…
Leaking samadhi is valuable. It’s a quantitative shift in experience and perspective. Non-leaking samadhi is a qualitative shift.
In the former there is still a self, still a world of forms, still a person doing practice intent on various objectives in their practice. We have to work on this side, this level, all of us. It can get very, very thin though, so both world and self become wisp-like.
In non-leaking samadhi, the person has disappeared, and joined the great single existence in which nothing ever arises or passes away, even while all things arise and pass away. So nothing is left to leak in or out of anything.