I think it would be a good idea to not hide columns from users on the main board but to only allow them to see a certain saved view based on their user type. Ex: Guests can only see the guest/simplified view. Members get access to a more detailed view…
Or at least a default view.
+1 to this for both ability to set the default view on a board/project, and also restricting guest users to only certain views. Would be very helpful to allow clients a simplified dashboard view or kanban view with certain filters etc, and not let them change the view or filter settings. HUGE problem working with clients - Monday is too complex for them and they get confused quickly.
This is somewhat related to Feature Request: Private Notes / Hide from Guests
Though I think in general it would be nice to have more generalizable permission settings to hide an entire item, group, or columns from guest users, rather than just updates/info boxes on a pulse as that thread indicates.