My previously owned boat came with a spare prop that's worth $1K or so. It's still on the boat but I'm not sure why. I have no way to change it. I suppose if I found myself needing a prop I could supply it but find a shop to do the work so I wouldn't have to shop around for one and then wait for it to be shipped.
I don't think I would fork out the $1K for a spare if I didn't already have it but I won't be more than several hundred miles from home in the USA. It might be a good idea in third world cruising areas, but I would want the puller and extra hardware