Two corners, because one is never enough
In a multi-cat home a single fitting becomes contested territory. Even a single cat usually has a grooming spot and a scratching spot in different rooms.
Cover both rooms
Fit one groomer where your cat greets you and one where it sleeps. Those are the two corners it marks most.
Spares for the consumable
The scratch mat wears through where it is used hardest. With the set you cut a fresh piece instead of reordering.
£64.99 instead of £75.96
Buying the four pieces separately costs more. Nothing else changes — same pieces, same fittings.