I think it has rather a lot of relevance to the "return to service" part, even if it is just a matter of public perception. From the airline's point of view, life is being sucked out of the planes as they sit outside in various conditions getting cold started once in awhile. I'm not an engine guy nor a Jet guy, but from experience engines that sit idle have a much shorter service life, at what point this kicks in for Jets I won't even pretend to know. More than once I have met people who were thrilled to buy an older, low-hour yacht only to have to do an engine replacement in their first season while the purchaser of the one with the high hours, worn interior but a well-cared-for engine just keep on chugging along into antique status.