Why do we choose those 3rd parties libraries for Excel ?

Why using NetOffice?

We are using NetOffice mainly for preference reason, you will get the same perforamnce using the Interop assemblies.

Why are we using Excel-DNA?

Excel-DNA is an independent project to integrate .NET into Excel. With Excel-DNA you can make native (.xll) add-ins for Excel, providing high-performance user-defined functions (UDFs), custom ribbon interfaces and more.