Hm, super-useful was a bad term. The actual impressions I got were "obviously coherent and not bs, and with high enough mean+variance that the value of investigation is very high". Not necessarily the value of any one specific person investigating, but the value of it being investigated.

So I went a bit further than your

Now I'm worried comment-readers will think I'm a supporter of meditation (an out-group belief?). It is more accurate to say I went from immediate dismissal of meditation to a position of seeing the act of meditating as separable from a mystic context.

to believe the top of the curve was a) grossly useful and b) of non-negligible likelihood.