Are there any applications of analytic properties of generating functions which don't require complex analysis?

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I have seen on multiple places that complex analysis is used in analyzing generating functions and appropriate sequences, for example in "Analytic Combinatorics" by Flajoler, Sedgewick and "Generatingfunctionology" by Wilf. However, are there any applications of analytic properties of generating functions which require only real analysis? I have seen that there is one asymptotic approximation of coefficients that is based solely on real analysis in the abovementioned "Analytic Combinatorics", but I'm interested to see more example which don't necessarily have to be related to asymptotics. And also, I would love to hear general opinion of people, are generating functions basically just formal power series without complex analysis?