The unit error is in the comparison between USD/year (a rate) and USD (a value at a single point in time)
Apparently several people decided this fact was necessary to downvote ¯\_(ツ)_/¯
Though GDP is usually calculated on an annual basis, it can be calculated on a quarterly basis as well. https://www.investopedia.com/terms/g/gdp.asp
Another example, look a records when the physical pools are slightly off of regulation distances for 100m/200m etc. Record keepers in no way ignore those differences.