The simple reason is that if you design your language with limitations of a quantum computing you can make certain guarantees about your program being able to p

The simple reason is that if you design your language with limitations of a quantum computing you can make certain guarantees about your program being able to physically execute on any quantum computer. You can find more details here: https://learn.microsoft.com/en-us/azure/quantum/overview-what-is-qsharp-and-qdk https://learn.microsoft.com/en-us/azure/quantum/overview-wha...