Why Result<T> doesn't provide an implicit conversion for Exceptions?

[MrBogomips]

Instead of this (notice the double new):

Result<string> GetAstringOrAnError(bool isError)
{
	if (isError) return new(new Exception());
	return "Hello";
}

It would be nice to have simply:

Result<string> GetAstringOrAnError(bool isError)
{
	if (isError) return new Exception();
	return "Hello";
}