I think it would be a missing part of the puzzle if integrations can show a (filled) card or section on a device page, ready to import to a dashboard/view with one click!
e.g. vacuum integration could show prefilled vacuum card, in addition to the current fixed entities cards shown for diagnostics/configuration/sensors.
In the case of hacs / custom stuff these could also be custom cards (esphome energy meter could configure this to show energy graph).
These could even be used for the auto-generated dashboard.