That's true, but it can be a lot of work to set up a new employee with benefits, stock options. Also maybe there's a signing bonus, a new laptop and other office equipment, relocation, visa sponsorship, etc.
I think it's better to start as an independent contractor (and work remotely.) Then there is the expectation that this is a short-term contract, unless everyone is happy and wants to continue working together.
You can just quit during your trial period while on a long term contract...