I'm not sure what "gurus" you're seeing but it's not really relevant to objective studies that show it works and makes changes in the brain. I'm sure they are making some claims that are pseudoscience, but that doesn't mean meditation in its entirety is just a "feel nice" routine.
Here's just one of several I found in a quick search-
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4895748/
I think of meditation as exercise for your brain. Just like you need to physically exercise to "prepare" your body you need to be doing stuff to keep your brain from going haywire and jumping from though to though like its hopped up on caffeine all the time. There are various ways to do "train your brain" but meditation/mindfulness is one very good way to do it.