Near-death experiences are neither illusion nor insight. The various kinds of near-death experiences are scientifically explainable in terms of the different circumstances in which they arise.
The term “near-death experience” as it is used at present is unscientific and makes research difficult.
“Near-death experiences” are a proof neither for nor against the existence of god or the supernatural.
Science and religion are separate things.
Apart from this, as for every life event, near-death experiences also shape one’s personal world view. Naturally, this may include spiritual views among other things.