I recently tried to import my contacts from an Excel file (XLS/XLSX) into my email client, but I noticed that these formats are not directly supported. I have seen CSV or vCard (VCF) formats being recommended instead. Can someone explain why XLS and XLSX are not considered standard contact formats for email clients? Also, what is the best way to convert or import Excel contact lists so that they work smoothly with Gmail, Outlook, or other email services? I am looking for reliable methods or tools that can handle large contact lists without losing data.