Pointing back to a post from the past “Gains from Meditation“, worth reproducing in entirety here:
Someone once asked the Buddha skeptically, “What have you gained through meditation?”
The Buddha replied, “Nothing at all.”
“Then, Blessed One, what good is it?”
“Let me tell you what I lost through meditation: sickness, anger, depression, insecurity, the burden of old age, the fear of death. That is the good of meditation, which leads to nirvana.”
And the beauty of it, is that we can all experiment with it and reach the same conclusion.
I can vouch for the efficacy of meditation and allied practices and have written about my experiences earlier.