List/Grid delegates currently aren't accessible, which makes a large portion of System Settings inaccessible.
This is primarily due to the fact that they often include focusable controls, which violates the expectations of blind users and others relying on strictly keyboard navigation.
The expected UI is that tab is used to enter/leave the grid/list, while arrow keys are used to navigate between items in the grid and list, and space/enter is used to trigger the currently selected item if it has an associated action.
Putting focusable controls in the delegate at least violates the expectation of tab behaviour, and in the case of controls such as text fields, additionally the arrow key behaviour.
This is a large accessibility issue and needs to be addressed if we wish to give users relying exclusively on keyboard navigation a good user experience.
Besides violating expectations, there's also some other usability issues.
Given a sufficiently large count of items, tab focus will not be able to get to items after the grid/list within a reasonable amount of time, and when utilising stuff like search, it's possible for focus to get in the middle of the list, in which case exiting the app is the only way to get out of the list/grid view within a reasonable amount of time.
On the technical side of things, focusable controls in list/gridview delegates additionally yield many bugs which compound on the design accessibility issues.