Looking at the Kee Beach photograph....it does appear a very long way between beaches suitable for any kind of landing. It is not how many places there are to land....but if there is one available when you need it. I don't see that being the case in the Kee Beach photograph.
What do the beaches look like at High Tide? High and dry as in the photographs?
The FAR that says "in case of engine failure" explains the FAA mindset.....they ignore about a thousand other reasons one might find himself bobbin' in the oggin'.
Please to remember this is the exact same FAA that agreed with the airlines when they asked to remove life rafts from flights operating along the East Coast of the United States. They argued and the FAA accepted it being a statistical improbability that all three engines of a 727 would fail and thus life rafts on those overwater sectors were not needed (....more passengers could be carried I guess).
Two weeks later, an FE got the board confused, and managed to flame out all three engines. The crew managed to get the engines restarted but it was a close....close thing. The same FAA then decided rafts were a good thing for airliners.
Of course this is the same FAA that takes a hands off approach to the Gulf of Mexico Offshore Industry as well. How many deaths we see down there last year?