I like that approach. In Vegas, many aspects of the market are saturated. Would another glitzy, overpriced Strip hotel/casino succeed? Probaby not, at least not if it lacked any way to distinguish itself from the crowd. For instance, Circus Circus appeals to people who like Pepto-Bismol (the color).
Most people don't go to Vegas to "get healthy," but quite a few people don't go there to reduce their lifespan, either (though statistics do show that a day spent in Vegas takes away approximately 3.9 days from your life expectancy). For some, healthy eating options, opportunities for excercise and fitness, etc. might be just what they want. It's a potential niche market.
There are many such niche market opportunities that have been successfully exploited in the past. For instance, the California caters almost exclusively to Hawaiians. In the locals market, Dotty's caters to chain-smoking middle-aged women who bite people.