The starting point is the the version 3 (v3) of the model Contoso 1M - currency conversion optimized in the Sample Walkthrough workspace. By selecting this version, you see the state of the model at the end of the previous step, after we marked a few measures as Ignored and other measures as Fixed.
The Overview page now shows there are no issues in the model.
The Issues page shows that the issues we ignored in the second version are still ignored in this third version.
Once we activate the filter of fixed and ignored issues, the list is empty.
You can still use the Measures page to see the relevance of the measures in the model. You can still have expensive measures in the model that do not have issues reported. In that case, you have to evaluate how to change the algorithm to reduce the complexity of the calculation. At that point, DAX Optimizer is still helpful to figure out how to prioritize the optimization efforts in the measures of the model, even though it cannot provide suggestions about the changes to make.