If you add the value/count summary to an opportunity pipeline kanban board, the summaries will only be shown for the open statuses. It would be great if these also showed a value for the positive closed statuses so that our users can review how much of that pipeline has converted into actually sales and how much is still in the pipeline.
I think it would be better to just use reporting to find out this information so that you can set date ranges for sales, and perhaps group by pipeline.
Unfortunately the way the kanban works is that there is a potentially unlimited number (infinite!) of opportunities in the closed status, so summarising this value would be expensive (processing) but also somewhat meaningless. Meaningless because there's no date context - i.e. it woudl be the total value ever sold which could be a week, a month, ten years ... depending merely on how long you've been using this pipeline...