Your question is a bit like this: "I am a programmer by hobby, and I learned about von Neumann machines. Why should I care about them?" And the answer is: because they're the theoretical model of computing machines that transformed our society.
Your question about the $\lambda$-calculus has a similar, but less grandiose answer. The $\lambda$-calculus was invented before Turing machines as an answer to "what is computation?" In itself it is not terribly practical, but it has been immensly influential in programming. Many programming concepts that we use today originated in the $\lambda$-calculus. Various languages support $\lambda$-calculus to various degrees, but almost all of them are in debt to $\lambda$-calculus to some degree (even the ones that are claimed to be "anti" $\lambda$-calculus).
If you are a hobby programmer, you should learn a programming language with good support for $\lambda$-calculus, as that will give you the joy of actually using the concepts. For instance, you can try one of the following:
Many popular languages have partial support for $\lambda$-calculus, which they implement to varying degree. If you know one of them, you could try the functional programming style (which is what $\lambda$-calculus is about), but keep in mind it's not the Real Thing:
LISP belongs to this list as well, as it does not have true support for $\lambda$-abstraction.