I've been using textbooks to learn things for over 50 years and during my development writing code many (most?) of those times was not in the context of a classroom but in the context of needing to understand something so I could write code to do it. For folks in this situation having answers, especially to some complex problems, is a huge benefit in terms of gaining understanding and saving time.

I don't think I'm alone here when I say I frequently gain understanding of things by writing code to model them. I know I understand something when I can write it in code. So after ingesting the lesson about a topic I'll see if I can write code to do what I just learned. I have spent a lot of hours stuck at a juncture of not being entirely sure my code, which works on the simple examples, is also working in the complex ones. The difference in results may not be evident. Am I troubleshooting my understanding or my code? I need a known result to actually know.

This is one place being able to copy something from your textbook, for example, paste it into ChatGPT and ask questions is a huge benefit. ChatGippity doesn't always get it right but usually the interchange is much more useful than being stuck.