Why should I care about lambda calculus

I am a programmer by hobby. I stumbled upon lambda calculus from Kevlin Henney’s talk lambdas to the slaughter and I was sold! It was an interesting new way of thinking that’s entirely different than the way most of us program. But if I want to push someone to learn lambda calculus, what concrete benefits can I state.

I tried for long but the only one I could come up with is that its fun to play around. And it acts as the base of functional programming.

P.S. when I first heard about Lisp I couldn’t understand why so many C brackets. After spending some time with lambda calculus, now I know ;P