Well, you have the right to exercise those options and then they become stock and you have a stake in the company. The nice part of it being an option is it grants you the right to invest in the company at a static price if you choose. And you choose to do this when the company is doing very well.
No. Options can only be exercised if the owner(s) allow it. They can just as easily decide not to exercise them and revalue them at $0. This is generally considered unethical and would dramatically impact retention, but there is no explicit guarantee in options. It is implied and their value is entirely at the discretion of the owner(s).
