I hope the card format is not an orphan format either. I bite the bullet and got the 160 Gb for the A1 but would like to have the 80 Gb for the A7Siii. I'm waiting to see how well Delkin will perform. I'm currently using their SD cards with success in the A7Siii.
I don't understand the logic of some cameras having one CF Express type B card and the other slot is SD Card - I think having the option of SD Card and type A card slot would make more sense for preventing bottleneck buffering.
Well, they put in the CFexpress type B slot for two reasons: the type B has extra lanes, giving it the ability to be much faster than the type A (whether the camera can write that fast is an interesting question...). And the type B slot is compatible with XQD cards, so if you were offering XQD capability in your previous cameras, then this lets your customers continue to use their XQD cards.
But putting in two type B slots (if they'd fit) would block compatibility with the myriad of SD cards out there, so they go for one type B and one SD. Note that the sizes of the cards means you can't make a slot compaible with both type B and SD.
There's a long history of having two different slots in higher end cameras - higher end bodies offered one CF and one SD for a long time, then some had XQD and SD. It was irritating to need two different types of card if you wanted to record to two cards at once, but it made the cameras compatible with a wider variety of cards.
I like having two slots the same so I can carry a bunch of cards of the same type, and not have to care about having enough cards of two different types. The dual format slots in the A1 make me happy, but I'll be even happier when the price of type A cards starts to come down!