It is statistical trickery and a headline number used to make people think things are OK. It is also a convenient number for COLA increase targets which make people think their incomes/pensions are going up (when effectively they are not on a real basis.)
Also, as you note, we re-baseline each year and dont talk about the cumulative compounded inflation e.g., over the past 5yrs.
Americans on fixed incomes (e.g., pension, social security) and those without wage elasticity (e.g., restaurant workers) are absolutely miserable right now because they are squeezed from both sides, even after modest wage increases in 2021/2022. This is not good for a Democracy.