What PDF is
PDF describes a page: glyphs at coordinates, not rows and columns. A table in a PDF is a visual arrangement, not a data structure.
Reports, invoices, statements and anything sent to be read rather than processed.
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 PDF to Excel
Every character in a text-based PDF carries its position on the page. Characters sharing a baseline are one row. Columns are found from the vertical strips no character ever occupies, which is why extraction works cleanly on a document laid out with spacing and badly on one laid out with ruled lines. A header repeated at the top of each page is detected and dropped rather than landing in the middle of the data.
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.
The table is reconstructed from character positions rather than read, because a PDF stores glyphs at coordinates and not rows and columns. Columns are found from the vertical gaps that hold across the whole page.
Values are written to the spreadsheet as text. That is deliberate: a figure pulled out of a report often carries a currency symbol or a thousands separator, and letting Excel guess at those is how a column of amounts turns into a column of dates.
Check the result against the PDF before you build anything on it. The extraction is a good guess and it is still a guess.
What carries over from PDF to Excel
Excel can express everything PDF holds about a table, so this conversion is about shape rather than loss.
Excel wants a type for each column, and PDF 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.
This is the direction that recovers structure: PDF has no table in it to read, only an arrangement that looks like one, so the rows and columns are inferred rather than read.