Why are tables important in Outlook?
Screen readers keep track of their location in a table by counting table cells. If a table is nested within another table or if a cell is merged or split, the screen reader loses count and can’t provide helpful information about the table after that point.
Blank cells in a table could also mislead someone using a screen reader into thinking that there is nothing more in the table.
Screen readers also use header information to identify rows and columns.