They often are. What is happening more and more is hybrids. What's going on with the amount of digital sales in K to 12, notwithstanding the obvious progress that's being made, is literally minuscule, and based on current funding for schools for hardware, infrastructure, and getting the teachers up to speed, we are many years away from digital being the answer, and even then, I'm not sure the printed book won't have its place. I believe it will for some time.
Digital alone is absolutely not really all that helpful in the medium term.