Sailing solo would be a reason to go outside. Can't imagine doing the ICW solo with its constant need for vigilance and traffic in often very confined spaces. Even with an auto pilot, there will be precious few opportunities to leave the helm. Getting in and out of strange marinas, should you chose to go that route, would be especially challenging.

You don't have to go outside the whole way but it could take weeks off a trip south even with stops. I sailed from Tampa to Norfolk in under three weeks with stops in Marathon, Fort Lauderdale and Charleston. No auto pilot or self steering so did have one crew member for the trip. With A/P or self steering, wouldn't need a crew. Could even do it solo with stops for sleep every two days and still make good time.