Besides charging batteries the engine is useful for a bit more than getting in or out of harbor. As well some harbors do not allow sailing. There is a thread on here where the owner tries to put an outboard on a 32' Irwin and after a lot of work gave up. There's a very good reason you seldom see an outboard on a boat over 25' or so. They just don't work well. An inboard is a lot less hassle in every way I can think of.
Living aboard in Victoria Harbour