I did one because it happened to be right along a route I was doing and It was NOT worth $7.
I had planned it as a fun stop on a long afternoon shopping with my 5 year old. I figured I could get him an ice cream cone and I would have a good excuse to sit for a few minutes while I read the menu. I happened to get a trashy McDonald's attached to a gas station. The bad language being used (by other customers) was so bad I felt like I needed to keep my hands over his ears!
We sat in the closest booth to the cash registers and I could hardly read the menu. This particular McDonald's had an old style of menu with teeny tiny font. When I was done with the prices and needed to take the pics I knew there was absolutely no way I could subtly take pictures that were close up and clear enough to read the 10 pt font. I just decided to go for it and stood up and took a bunch of pics with my phone, when I got a funny look from the cashier I just said it was for my husband so he could decide what to eat.
I was able to use the mobile app and fill out all the prices on my phone so that was easy, I don't think I would want to do it if I had to take paper notes, no way to be subtle about that.
The moral of the story is that if they are bonused enough and you happen to know that the McDonald's has an easily legible menu board these might be worth it. Otherwise prepare for 40 minutes of eye strain and dirty looks from the employees.