Format shifting is settled law — in favor of format shifting. The problem with Blu-ray would be the horrible DMCA.
My benchmark for whether the terms of a EULA would be IMHO enforceable and not an abuse of copyright is to apply the high-level general concept to a book. If it sounds okay, then it’s not copyright abuse.
Telling you how and under what conditions you can read a book sounds like copyright abuse to me.
Not format shifting for resale. A company cannot shift the format from one to the other and then sell that product for a profit without the express written permission of the copyright holder. Individuals are allowed to shift content to other formats without permission for their own personal use so long as they do not modify the content or transfer the original format while keeping the copy, or vice verse.