Inflation is the rise in price of every single item for sale across a market, not just the "basket" of goods selected to be a good example, and subject to adjustment and correction over time.
It is entirely possible that inflation that averages out to 10% for a year may double the cost of living for some people, and actually make things cheaper for others.
Scalars are 1-dimensional. Inflation is very much a one-dimensional number, ranging from positive to negative.
Vectors have 2 or more dimensions, interpretable as a scalar with a rotational direction. So how would that describe inflation exactly...?
And if you're trying to say that inflation changes over time, that doesn't turn it into a vector. That's just a scalar time series.
It's (2, 0.5).
You could turn this into a scalar if you want to. But you have to throw away information to do so. Or, to put it another way, you have to select a subset of the information.
You can't interpret the inflation vector as a direction, because inflation space is not a metric space (or something - the particular genre of vector spaces where geometric concepts are meaningful).
The difference is direction. Are you just warning about deflation?