Good finding. It's a reasonable guess
that they want to discontinue the no-annual-fee Sapphire, but who knows. Hopefully this is just something that reduces the browse credit card page size.
By the way the Disney card
has the same situation, it's removed from Browse All Credit Cards page, but can be reached through Disney Premier VisaÂ® Card
Marriott card is similar, though both versions have annual fee.
Guess the next step would be the United MileagePlus cards?