Building on a raised foundation is not that costly, just raise it on wooden pilings eight or ten feet and park your cars beneath, that’s how practically all beach cottages are set up on the southeast Atlantic coast. Some go further and have a raised garage or parking area so their vehicles are above the 100 year flood plain, historic storm surge averages or whatever standard they’re going by.
Scouring effect.
You have to have footings and connectors and posts that withstand that. Also depends how far down you have a solid base. Still pretty darn expensive. Also, when you’re up in the air like that you have wind uplift to consider. Lot’s more expensive to mitigate that.
Those beach cottages on stilts you see are usually not designed for hurricanes. Cheaper to rebuild.