Sigh, people always trot out the Simpsons meme.
This may in fact be a good use for monorail. Most of the route is over water, so it's gonna be elevated on structure regardless of what technology is used (and monorail is the least visually imposing kind of guideway and quietest). It is not, nor does it need to be, part of a larger metropolitan system so the usual concerns about switching, branching, etc are moot.
I really don't see how this is different than the way Japan uses monorails, as a medium capacity solution where an expensive metro line isn't warranted, *or where waterfronts make underground construction difficult*. And the Miami line would be tourist oriented to boot.
The only question is on the Miami Beach end - the tourist area (and employment area) is spread out and likely requires several stations to serve it effectively. Are Miami Beach residents willing to accept an elevated guideway running along major streets on their island, Alton Road or Washington Ave? If not, then a monorail is a poor solution as it will never be extended past Alton Road.
This kind of stub terminal is a horrible idea unless there are firm and realistic plans for further extension, because with the monorail technology the future extensions cannot run at grade.