My personal experience I did buy the decals without consulting anyone. They did not help me at first to LEARN the fret board but this was in the beginning stages of playing bass where it all sounds so difficult. One day I decided to get over my fear of feeling stupid if I couldn’t figure it out. I picked up the bass with the decals and look for repeating patterns and then applied the “down the scale flat, up the scale sharp” rule. After doing this I could Identify every note on the fret board within 24 hrs. I started by focusing on natural notes first and looked for patterns that repeat over the fret board that are easy to identify like BC and EF. BC on the A string and EF on the D string. These sets of notes appear together on several other places on the fret board.
Identify those and from there apply the sharp flat rule and the light switch should turned on like it did for me. The decals are useful for identifying the other BC and EF notes fret board. After you do this go to the 7th fret when you look at the decals you will notice that the 7th fret, from left to right, spells the word “BEAD”. From there follow the sharp flat rule. Being able to see BEAD burned in my mind that the notes on the 7th fret spells BEAD. I believed this happens because the decals provide you with the visual assistance. I will just say it depends on how you use the decals. If you use the decals they way I described to you, yes, it can be and effective “cheat sheet” and can make the learning curve a lot shorter and save you time and frustration. This is good if you are like me and pick up the bass in my 50’s. If guess what everybody else is saying would be ok if you are kid that has a lot of years left to figure it out, LOL. If this does not make sense to you message me and I can explain it in detail. Also you can go to this page in the Theory Forum of this site where I tell the whole story. I really thought I was doing something!
One more thing, if you read my about experience in the Theory Forum what I was referring to as “Whole Notes” are actually called “Natural Notes”…Josh pointed this out to me. So all the places where I wrote Whole Notes replace it in your head with the term Natural Notes.