He advises hikers on the Via de la Plata to get a credencial so that they can stay in albergues.
We've had discussions that some (not all) albergue owners or the groups who manage them require that those who stay with them are walking as pilgrims to Santiago.
The albergue in question (
In Aljucén, for example, pilgrims can get a dorm bed in Albergue San Andrés for €12 and a menú del día in the village bar for just €10.) is an interesting case. The link in the Guardian article points actually to this forum where the description is a bit different from the
description on Gronze where it is described as
not exclusively for pilgrim but oriented towards pilgrims and they accept reservations. IOW, you can stay there without a Camino credencial.