We provide support services to clients. We find that some of our clients are running the latest system while others are still on Windows 2016, others are moving to 2019. Some other clients take time to upgrade. If I interact with five clients, I'll basically be in five different environments.
Our use case for the SQL Server is for transaction processing. We store all the transactions that occur. For example, if you now purchase something from the point of sale, all the information about the good you are purchasing gets stored on the SQL Server.
When you perform a transaction that information is stored at the bank that owns the point of sale and perhaps even your bank, where your money is will be stored in a SQL Server.
All the people in all of the organizations, which are involved in the process use SQL Server.
If your transaction goes through my server, I store part of the transaction there, and if I have to route that transaction to Visa or Mastercard, they have their own SQL Server, and they also store the transaction up until you get receive your goods at the particular merchant. Almost everyone in that transaction stores the information on their respective Microsoft SQL server.