I added cash using the symbol you mention, USD=X, via a Buy transaction with the price of $1.

Adding cash to a portfolio effects the risk-adjusted performance indicators for the portfolio so why would you say there's no point? Am I missing something?

Including cash to your portfolio affects the performance metrics you see, that's true. My point was that cash itself has no statistical properties to analyze (zero return, zero variance by definition), so from an analytical standpoint, the interesting insights come from your actual securities (where the expected return is not zero, etc).

If you want to see how your total deployed capital performed including cash positions, then yes, include it. But if you're trying to analyze the risk/return characteristics of your investment decisions, you'll get more meaningful insights by focusing on your actual positions.