If exporting simply (not clicking on "file that can be imported), then Shift notes do not appear as a column. You have to doubt-click the column in Excel with the shift reveal the shift note. Also, even if you uncheck daily hours and time off, it still exports them.
If you export with "file that can be imported" you lose cell shading colors (it becomes a column with the color written out) and each employee could have two or three rows if there is a shift note added.
Exporting to excel and then dropping into Slack loses spreadsheet presentation and puts each column on its own page. Quite a mess.