The EHR in itself as a system is of no use to the patient. A PHR is (Personal Health Record). There is plenty of literature about that.

Nevertheless, the date in the EHR are very important for the PHR. So Data Exchange from EHR to PHR is the far most important endeavor for health informatics. As a byproduct from EHR to PHR exchange also referral messages and such, including the International Patient Summary and similar have their use.

EHR as document has very limited value. Most value comes from data that are standardized according ISO 13972 Clinical Information Models. This would include textual data eg from a contact or note, but preferably using SNOMEDCT codes to identify either the subject or the concepts used in the notes.

The Netherlands has set up legislation and a set of agreements that facilitate EHR to PHR data exchange. That is the MedMij set of agreements. A good starting point is www.medmij.nl. There is an English page as well. MedMij invests is SNOMEDCT terms that are patient friendly (understandable)

Yes definitely, studies show that patients like the autonomy and flexibility that comes with EHR like making thier appointments online and medication refills and more. Here is an example of work that is done in this area, EHR services was more important than the physical and some structural services

Article Patients ranking E-health improvement initiatives in primary...

Re-reading the question, I think an addition is required:

besides clinical content, the generic EHR guidelines as expressed in ISO 18308 are perhaps applicable;

ISO 18308:2011

Health informatics — Requirements for an electronic health record architecture

https://www.iso.org/standard/52823.html#:~:text=ISO%2018308%3A2011%20defines%20the,)%20information%3A%20an%20EHR%20architecture.