All of these stats matter, because it shows multiple facets of a complex economic system.

Bottom quartile earnings are here.

Real Median Personal Income

I don't like using personal income as a metric that represents what's happening to regular people because it's noisy data that incorporates retirement income and investment income in the numerator, and includes in the denominator non-earners (including the idle rich, retired people, full time students).

But as part of a broader look at multiple metrics, it should be considered.

Others include the different categories of unemployment (including the underemployed, the weekly hours worked, marginally detached), read with other employment indicators like layoffs and volunary quits, job openings posted, people making unemployment claims for the first time, etc.