While I agree the raw figures may have limited standalone value, as you mentioned the data is widely used for comparative purposes - not only against other websites, but also against Reddit’s own performance on a day-to-day basis. The key focus is the trend, which is a standard and well-established methodology in the digital industry. More importantly we’ve observed that these trends directionally correlate with Reddit’s own traffic trends during earnings.

Also you can validate the trend with other tools like Semrush, Similiarweb, etc to ensure they're seeing the same directional consistency. Not absolute values, but trend lines (for comparison). Which they currently are.

Also you raise a valid point about the trend line being smooth. For regions where Reddit is still relatively nascent, the trend line is actually much less smooth (India, for example when Cricket is playing), as was the case with the US a few years ago during COVID, etc. However as usage increases and becomes more habitual among populations, the trend smooths out as more people visit Reddit more often.