Every tablet and phone I will ever own will include a MicroSD media slot. It is faster to move data via the SD slot from an older device to the new one. Plug it in and move on with life. No fuss, no muss. As opposed to devices that have no SD slot (only integrated memory) and require a connection to a computer or (slower) cloud storage device, which take more time to transfer and - in some cases - data corruption can occur. Just moving one expansion card is so much quicker.
I bought this 64GB card on sale, which was lower than any online retailer. But even if it were not on sale, it is cheaper to spend $50~100 on this MicroSD card than it is to spend up to $200 more between phones or tablets. Many devices come with 16GB, charge $50~$100 more to get the 32GB device, and then another $100 on top of that previous charge-up for the 64GB version. Keep in mind that integrated RAM is also being used by the operating system and data it stores.
So, for many practical reasons, we customers are better off with MicroSD cards that are transferable between devices.
If anything, as long as one doesn't bend it or tapdance on it, it will remain viable. My only worry is cramming 64GB of space into such a small domain. Technology is incredible, but flash memory devices have limited write spans (100,000 write cycles per sector) and the space between sectors is so small that electromigration or magnetism could reduce the ability of the card to hold data. Even as a digital photographer, I know that full size SD cards can corrupt image files over time. So backups are essential, and the smaller size of MicroSD makes backing up even more important. But SanDisk is, historically, a VERY good brand. I don't expect the card I bought to fail any time soon.