It's not like the seller is asking hundreds of dollars for this item.
If you can look at what is being presented prior to making the purchase, and you find it may be helpful to you and your specific needs, then buy it. Who gives a flip what others think?
It's small and pocketable, which is actually a problem with the typical cheat sheet. They are made small to make them portable and they tend to be so small that many older readers can't actually use them, particularly in lower light settings.
In the end, if you buy one, you'll probably only use the sheet for a short while if you are a consistent shooter. If you pull your camera out two or three times a year, then maybe the sheets will help on these rare occasions.
Practice is, of course, what will keep the ideas fresh in your mind.
The rules are really fairly basic so there's not a lot to remember. If you are using the semi-automatic modes of the camera, then there's even less to keep in your head. The camera does most of the figurin' for you. You simply need to give it a few very basic commands ... and remember to check the histogram before you take the shot.
If you know there are specific issues/settings/situations you have trouble with in the field, you might rather simply take your owner's manual and transfer a few explanatory pages to your word processing program to print out exactly the data you need.
In the mean time, go out and use your camera as much as you possibly can. You'll find there's less you need to have on a cheat sheet in just a few days time if you practice.