Why indeed. One comment from Cruising Mates [!] suggests :-
The other thing about Saga is they have less room on their ships for cabins as they have larger capacity morgues than is usual. A typical 70,000 - 100,000 tonne has 2-3 places, Saga ships have 5-7.
They tend to keep this relatively quiet, but i found out from my mother ( who has done 3 world cruises with them + other shorter cruises) as that is the sort of question she would ask , especially on the longer sea passages.