I came across the Lego Ideas and the original one, and it doesn't seem to have any difference. It's just a normal house, but on a book? Can somebody help me tell the difference, as my son wants to decide on his birthday present. Thanks!
The question is unclear, but I will take a stab at it.
It seems that OP found the LEGO Ideas website with the LEGO Pop-Up Book project: https://ideas.lego.com/projects/cfaf7a52-02a4-4dc0-8ec3-6b94d7c36069
Then they also saw this listing at the Online LEGO Shop: https://shop.lego.com/en-US/product/Pop-Up-Book-21315
OP thinks that both sets can be bought and is asking how the two sets are different.
To answer the question, the original LEGO Ideas submission is not for sale. Only the #21315 LEGO Ideas Pop-Up Book set can be bought.
How LEGO Ideas works is that LEGO fans can submit their own ideas they would like LEGO make into a set. If enough people like an idea and vote for it, LEGO will consider making it into an official set. Once the idea is selected, LEGO's own designers will refine the project to their own standards and make it into an official set.
The #21315 LEGO Ideas Pop-Up Book set is the result of the original submission at LEGO Ideas. It is the only version of the project that is for sale. The set is designed like a traditional pop-up book that can open with scenes that pop up from the pages.
The original LEGO fan project included suggestions for various scenes that could be used for the book. For the final set, LEGO's own designers selected two interchangeable scenes; Little Red Riding Hood with grandma's house, and Jack and the Beanstalk with a "growing" beanstalk. You can see pictures of both scenes and how they unfold and pop up at the Online LEGO Shop page: https://shop.lego.com/en-US/product/Pop-Up-Book-21315
I hope this answers OP's question. If I'm, completely off the mark and misunderstood the question and what set OP is talking about, please OP, come back and clarify your question.