A thin client is a desktop terminal that has no hard drive. All features typically found on the desktop PC, including applications,memory,RAM except of the hard disk.
You have your data at the main server and all the system act as a virtual terminals through which you can interact with stored data.
You can access the data and using it but the repository of the entire data is at one place.If your system or terminal gets damaged then there is no problem with the state of the data
Any damage to the system will not cause the data to be get destroyed . It is safe all the times
Thin client increases the reliability and security of data from the old systems