What LaTeX is
A LaTeX table is a tabular environment: a column specification, ampersands between cells and double backslashes at the end of each row.
Academic papers, theses and anything typeset with LaTeX or written in Overleaf.
What Excel is
An Excel workbook is a zip archive of XML parts describing sheets, cells, formulas, styles and charts. The .xlsx extension is that format; .xls is the older binary one from before 2007.
Finance, operations and anyone who received a file from finance or operations.
What changes when you convert LaTeX to Excel
The tabular body is read, rules are dropped, and escaped characters are unescaped. Text wrapped in textbf or emph is reduced to the text itself.
You get a single sheet with a header row and column widths sized to the content. Values are written as text unless type inference is on, which keeps identifiers like 0044 or 007 intact.
What carries over from LaTeX to Excel
LaTeX records 2 things about a table that Excel has no way to hold.
Excel wants a type for each column, and LaTeX does not record one, so each column is typed from what its values look like. A column of digits that should stay text - a zip code, a phone number, a leading-zero id - is the usual thing to check afterwards.
LaTeX can hold a value that is itself a list or an object. Excel has only flat cells, so nested values are flattened into one cell rather than being spread across columns.
Excel has no separate idea of a header, so the column names become an ordinary first row and nothing in the file marks them as different from the data.
This is the direction that recovers structure: LaTeX has no table in it to read, only an arrangement that looks like one, so the rows and columns are inferred rather than read.