A good library continually updates its collection with the most recent books published. Text books are often years behind current scientific discovery even when they are brand new. The textbook editorial process just doesn t allow for quick turn around. Libraries also carry a wide variety of magazines which offer the very latest in scientific discovery. If you are working on astronomy, you can read an astronomy magazine.
Magazine subscriptions are expensive.
It s so nice to have many different magazines to choose from at the library including all the back issues. That doesn t mean that a textbook can have no place in your homeschool. I have several elementary level textbooks that I purchased our first year of homeschooling. That s when I was deep into the school at home mode. Now I use those textbooks as reference points.