I'm looking at data model and there is column for date, year, week, yearweek.
Yearweek is concatenation of year and week.
What is the benefit of having the YearWeek column when year and week are available?
It can be used for various things. I have one in my table for sorting purposes. e.g. if you wanted to display "Week 3, 2023" in a table or chart as a label, you'd use your column as a sort by column.
It called about be used to simplify weekly time intelligence e.g. create a filter this many weeks in the past which easily crosses year boundaries etc