Excel is perfect when someone needs formulas, filters, and editable cells. It is less ideal when you want people to read a finished report. Columns can resize, formulas can be changed, and mobile viewers can make sheets hard to scan.
PDF gives you a shareable snapshot. It is useful for quotes, schedules, invoices, scorecards, price lists, and reports where the values should not change after sending.
Use Excel to PDF when the spreadsheet is ready to present, approve, print, or archive.