My apologies for prolonging your pain; I have found a defect in the way ALT Text data is returned and displayed after changes in the Quick Edit area. The values in the database are, in fact, updated but the old value is returned to the browser.
If you refresh the entire screen, or click the "Edit" rollover action for the affected item to go to the Media/Edit Media screen you should see the new value in ALT Text.
I will fix this defect in the next version. In the interim, I believe you'll find that your changes are being made but not properly displayed. If you find that's NOT the case, let me know.
With regard to your other question regarding the Media/Assistant submenu table, yes - the blue value in the ALT Text column indicates a link that will filter the display on its value when clicked. Many of the columns in the table have a similar feature; filtering the table listing by, for example, taxonomy terms or taking you to the Edit screen for a parent post/page.
Thanks for your patience, your understanding and your interest in the plugin. I regret the confusion in finding and fixing this bug.