Did you read the link I provided on recreational harvest -
these regulations are not new. Florida updates their list annually to stay on top of recent declines/etc. of species. It is pretty comprehensive and allows for harvest as long as their regulations are being met (e.g. license, required gear, etc.). So, harvesting lionfish isn't going to change what people take or behavior. Therefore, I really don't understand your argument. There are also commercial rules (link on side of page).
This doesn't apply in the Sanctuary. The Fl Keys National Marine Sanctuary is zoned with different level of protections, so you need to know what you can do where. I wouldn't collect in the Sanctuary,
Sanctuary-wide restrictions. It is double the enforcement there.
Having tournaments helps bring the number of lionfish in an area down in numbers. No, it won't eradicate the fish. I'm afraid they are here to stay. That is why we are trying to control the numbers in other ways. They may just end up being like nutria, which has spread and pretty much invaded the entire country now. Since lionfish don't have natural predators to keep their numbers in check, we have to figure out ways to do so. Why, you may ask, so we can protect our native species, both those we enjoy recreationally and commercially.