No historical data is going to tell us the future. But it can give us an idea of the trend, which is useful since in a large system like the economy the trend tends to change relatively slowly as compared to individual compentents.
A statistic is only useful if you know how to interpret it. Case in point: you can have double digit year-over-year inflation, while simultaneously falling prices for the last 11 months.
This doesn't make sense. Falling prices for what? CPI is a measure of cost of a basket of goods. You can't have net aggregate falling prices and a rising CPI unless you are measuring different prices.
It's just about how are you measuring the slope? Like, when you first learn derivatives and the math teacher draws a line between two points on a curve, then draws another from points closer together, then draws the tangent, then goes through how you get to a derivative function etc.
The yoy is just using two points very far apart. The mom is using two points closer together. It would be nice but practically impossible to measure it instantaneously, mom is about as good as we get.
Which is still stupid to even be arguing about. It’s like people are trying to find a problem with data that is objectively reported by arguing that if you change the x axis you get an entirely different conclusion. No shit… that’s how data works.