String interpolation ($”this is {name1} and this is {name2}”) was introduced with C# 6. It makes it easier than doing the composite formatting (“this is {0} and that is {1}”) approach and is easier to read. The composite formatting approach leaves room for errors by having the variables in the wrong order or missing them. When string interpolation is built it is compiled as if it were a string.format call.
If you have a string where you need 10 variables put into it and then you need to switch the order of those variables the composite formatting way can get messy. If you mis-count your variables and switch them then your string will be wrong. With string interpolation you can easily see what will be inserted where.
solved Differences in Console class methods