What you do after the being authenticated depends on what service/tool you are using.
Of course a private key let you do different things than an api key of an exchange, but some of them are in common, that's why i keep saying that can act as.
Can you use the API key to control your funds without using the website that issued the key?
BLOODY YES ! That's the fucking point you don't get. you can access every function of a service via any computer terminal without the need of using the website. What kind of functions you can access is based on the api key privileges.
...
...
...
How exactly do you think an API key interacts with the wallet the funds are actually stored on? You think there's some magic connection between the two? No. The website in question establishes that connection.
How exactly do you think an API key interacts with the wallet? It passes down a function for the wallet to perform. It doesn't substitute ANY of the wallet functionality (eg the private key transaction signing.)
To say that they have the same functionality is just stupid and ignorant.
Not to mention that Bitmex withdrawals are manually reviewed, so even a working api key is no garantuee for your funds. (Not that that was the main point).
Anyways...
You lied about your 495% returns. Case closed. "iT wAs JuSt BaCkTesTinG"
Your provided an API key to us with a couple of dummy trades because you think we're stupid? Or.. do you actually think anyone believes... the... backtesting? you sure don't mention it in your pretty infograph.

This is just misleading. If this was an actual business operation, it would likely be seen as fraud. You have NO proof of any of these returns. You implicating that the api key proves any of these returns is also false = misleading.
Really, looking at this image where you try to pass these imaginary results as legit i can only classify you as a troll