It is interesting that they are looking for someone who can complete an entire product cycle. Maybe looking for flexibility, if they are a consulting shop? Or seniority--someone who can do all that has been around the block? Or maybe they are such a small shop they can't afford specialists?
I have been in this full lifecycle role almost my entire career, often as a consultant, and it has benefits and downsides. You are always learning something new and have a wide view of the software world, as well as the ability to really dig into new toes of problems. But sometimes you feel a mile wide and an inch deep.