Google Sheets is Google's answer to traditional spreadsheet software and is part of the Google Workspace productivity suite. It is a cloud-based tool that allows users to create, edit and collaborate on spreadsheets online. 

1. Basic Spreadsheet Functionalities:

• Google Sheets offers the traditional functionalities of a spreadsheet application, such as creating tables, using mathematical and statistical formulae, formatting cells and much more.

2. Real-time collaboration:

• Similar to Google Docs, Google Sheets allows several users to edit a spreadsheet simultaneously. Each user sees the others' edits in real time, identified by specific colours.
• You can add specific comments to cells or regions of the spreadsheet and start conversations on those comments.

3. Version history:

• Sheets automatically saves a history of all versions of the spreadsheet, allowing users to see the changes made over time and revert to a previous version if necessary.

4. Integration with Google Drive:

• Files created in Google Sheets are automatically saved in Google Drive, providing secure storage and easy access from any internet-connected device.

5. Offline mode:

• Like Google Docs, Google Sheets allows users to edit spreadsheets offline, synchronising changes as soon as the internet connection is restored.

6. Compatibility and Import/Export:

• Google Sheets is compatible with other popular spreadsheet formats, such as XLS and XLSX from Microsoft Excel. You can import files from these formats, edit them in Google Sheets and then export them back to the original format or other available formats.

7. Predefined templates:

• Google Sheets offers a variety of predefined templates for various needs, such as budgets, calendars, project planning and much more.

8. Advanced Functions and Scripting:

• In addition to the common spreadsheet functions, Google Sheets offers the possibility of using Google Apps Script, enabling the creation of customised functions, automation and integration with other Google services.

9. Graphs and Data Analysis:

• Google Sheets allows you to create a variety of graphs based on the data you enter. It also has data analysis tools and can even connect to external data sources.

10. Extensions and add-ons:

• The functionality of Google Sheets can be expanded with a variety of add-ons available in the Google Workspace Marketplace.

11. Security and privacy:

• Similar to Google Docs, it is possible to share spreadsheets with specific permission settings, and Google employs robust security measures to protect user data.

To summarise, Google Sheets is a versatile and powerful spreadsheet tool that especially benefits those who value real-time collaboration and access to their files from anywhere.