If I go back and think about the past, what I would consider what was a sticker book. It was a book where you can place your stickers in. How you organized your stickers was up to you. With the digital age, you are using images as your stickers for your digital bullet journal.
Problems that comes with not having a sticker book.
Going into your images and choosing an image, you need to import one image at the time. This can leave you frustrated. You will permanently import a new image. Especially if you accidentally went and flatten it on your page, you are working on and you still wanted to use that image on another area of the page. This will mean that you will constantly have to go and import the same image repeatedly.
Some programs that you can use, you do not have the option of being able to copy and paste an image. You have no other choice but to go and import an image every time you want to add an image. There are times, when you do not even have the time to go and import every single image you want to use, when you want to use an image on the correct page this will leave you to go with one of two options:
Option 1 to use the bullet journal without stickers. Option 2 where you will not even use your bullet journal anymore. So why have a bullet journal if you do not use it?
Why use a sticker book
The sticker book is an area where you have all your stickers together. How you organize it? It is up to you, but the benefit of having a sticker book is that you can go and import all the stickers one at a time, only once. We can go afterward and copy all the stickers in the sticker book that you will need for creating a bullet journal spread. This can be copying all the numbers that you need for you weekly dates. Then rearranging it after you have paste the numbers onto that spread where you want to use it.
This can free up a lot of time and in some cases depending on what you use to have a bullet journal spread more colorful. This can be anything from having something written decoratively as a sticker in your bullet journal or having an image. That is only for decorative purposes to show what your theme is for that month.
An alternative option to use a sticker book
The option it is more for those they do not have a problem of always adding images one by one using another software. That can be for creating images the most common one would be procreate.
Some people will import a bullet journal spread in a software that is for creating or manipulating images. Well you can also combine multiple images into one image. This will give you another problem and another option, to organize your images.
You can easily import all the images you will need. This can be anything from having the entire sticker kit in one folder or in multiple folders that is dedicated to a particular type of image. For instance, a folder for all your numbers and a folder for all your week titles. You can even go add multiple sticker kits where you will have all the images like number images in one folder. Those files can be an alternative way of doing a sticker book.
Creating your sticker book for digital bullet journal
To create a sticker book it is to have a PDF document where you at all your stickers. The key here is to have a PDF document where you have saved it, not to have the images flatten. That is when you go and open the PDF document in the software that you are using for your bullet journal. You are still able to go and copy the image direct from the sticker book
Organize your sticker book can be something like having all the numbers in one place. You can decide all the same colored numbers to follow in order, or if you want all the number ones of all the different colors together
One sticker book or multiple sticker books
One or multiple, that will be the question. You will have to be able to answer, but if a question must be answer for you. Do you want all the images of your sticker kits all in one place? On the other hand, do you want to go and keep the sticker kits separated and how do you want to keep it separated.
This is more of a personal preference then a strictly given answer. It is up to the user to decide whether he or she want to go with one sticker book a multiple sticker books.