Good point. It's exactly like that.
Is there an afterlife? Do we reincarnate? We'll find out for sure, soon enough. The only requirement is patience.
Yet it is possible to know some of these generally unknowable things. Although perhaps not all.
It is a case of diminishing returns.
The energy I have expended and the time taken to expend it, to know what I know, is probably absurd.
Yet we undertake such expenditure, if we are so inclined.
I have no bias towards the existence, or not, of UFOs.
If one makes itself sufficiently in-our-faces, we will know about it, so there is no point.
But these dancing, zooming green lights I have seen...
Whatever they were, they were definitely there.