To me it adds about as much value as dealer glass etching, fabric and paint protectant, but Honda knows what they're doing in terms of selling OPE.
My low-end Honda steel decked, single speed self propelled, GC powered mower has been neglected and still runs like a top. It's 17yrs old. First year of the GC engine. I tore the cable out of the transmission years ago on a tree branch, so it's just been a push-mower.