Yes, there are some instructions around, but as I already mentioned, some use digital and some use analog pins.
In my fist test, I used analog pins and it seemed to work.
So where is the difference?
Should be no difference since analog pins can be configured as digital pins. I was under the impression that you were referring to code that in some way was using the analog pins as analog input pins for intefacing the device, which would seem really strange. It's just good practice in my opinion to use digital pins for digital I/O so you don't at some time, for example, expand a project and use one of the libraries such as the "wire" library, for example, that uses A4 and A5 for SDA and SCL - just things like that. But if this is all your project does, then no problem at all.