I just wanted to add my vote that I have not heard the INSERTED/DELETED tables being called "magic tables" before. I am also not sure what "deep information" you are hoping to get about them. If you had some specific questions about them, we can probably help or point you in the right direction.
Overall though, I agree with irgp's comments. Expanding on them, knowing the internals for how SQL does things in the INSERTED/DELETED tables is interesting knowledge, but doesn't really help you that much in your day to day duties as a DBA.
If you are applying for the job, I would say go for it. Best case, you get hired. Worst case, you get asked questions you don't know the answers to and have a good base for what to train on next.
I know when we were hiring a Developer (C# and SQL), I helped design some of the SQL related questions. Two of my best ones (as they helped filter out a few people) were:
1 - Can you explain the difference between a LEFT JOIN, a RIGHT JOIN, and an INNER JOIN?
2 - Can you explain the difference between UNION and UNION ALL?
Question 1 is pretty easy and even if you don't know SQL, you can get a pretty good guess from the names. And if the interviewee explained those 3 and some of the others, they got bonus points. Question 2 is one that I've seen experts get caught by before when doing presentations, which is why I have it in my back pocket as a good interview question. Most of the interviewees had no idea what the difference was, which was a little surprising, but at the same time I gave credit to ones who admitted they didn't know and guessed anyway. The ones who confidently gave a wrong answer got negative bonus points. In the end we hired someone who got question 2 wrong, but they told us they didn't know the difference, but explained what UNION did and that it was something they would look into. When they got hired, they came to me and my boss (who did the actual hiring) and explained what the difference was so we knew we hired the correct person for the role! Someone who doesn't know everything and is willing to learn.
The above is all just my opinion on what you should do.
As with all advice you find on a random internet forum - you shouldn't blindly follow it. Always test on a test server to see if there is negative side effects before making changes to live!