Spreadsheets are very helpful and easy to use for quick manipulation and presentation of data. However they have a number of problems:
One bad sort, or an accidental deletion can destroy your data. You can create backups, but very quickly you can end up with too many spreadsheets, with different data, and it can be very difficult to tell which one was the original.
Sharing data with a spreadsheet can become problematic. You can send around copies via email, but if one person makes an edit, it would need to be shared again, and it is very easy to have conflicting versions. The data can be collated into one original sheet, but this is an imperfect solution, as it is a) time consuming, and b) prone to mistakes.Public or cloud-based spreadsheets solve one of those problems (sharing) but it is again difficult to maintain a reliable and authoritative version.
You can easily end up duplicating content, which can easily cause inconsistency in your information.