The other issue is where staff are unsure when a service will be starting up again. A particular station might have services supposedly resuming in an hour, but if a staff member has advised you that train is also likely to be canceled, then would it not be advisable to use an avoid point to avoid the selected area? I know I use avoids all the time to find passengers alternate routes during disruption or unconventional routes with a couple extra changes that has the same arrival time. For example, direct Manchester to York service is cancelled, however putting an 'avoid Huddersfield' shows a change at Sheffield/Doncaster which is quicker than waiting for the next direct service.
Final point, via/avoid points can also generate longer itensries, but during major disruption, if you can avoid major over crowding, that's a win on safety grounds. If a passenger wants to take a longer but more comfortable route, the railway should let them. It prevents crushloading by allowing more services to bare the load.