The rationale for having user accounts for everyone in the directory that has an email address is
i) they can edit their own household
ii) you can put the address list in a shortcode or Gutenberg block, safe in the knowledge that only logged in users can access it.
iii) allowing people to edit themselves keeps you GDPR compliant.
Older folks without email addresses are unlikely to want to access the address list on the website – no email address generally means no ISP account anyway to get on the internet. You can provide them with a PDF print out!
If you don’t want people to be able to edit their entries or having the address list on the front facing part of your site, then they don’t need website user accounts.
Hope that helps