The information can be edited, so you can ignore some information by blanking it out, but this doesn't work for titles. If they're blanked, then the TITLE field is removed. Even if it did work, it would be a lot of work if you just wanted to retrieve something like track numbers.
Seems to me there should be some checkboxes in the tag sources dialog to select which fields you actually want. Am I missing something or is usability really as poor as it appears?