"dotnet tool exec" is not that feature; you're thinking of https://devblogs.microsoft.com/dotnet/announcing-dotnet-run-... which they added to "dotnet run". "dotnet run my-cool-thing.cs"

"dotnet tool exec" is so you can run third party command line tools like csharpier that previously required "dotnet tool install" before you could use them. For example, in https://csharpier.com/docs/Installation you can now simply do "dotnet tool exec csharpier". This is like "npx" in the JavaScript world.