Apple's new MacBook Pro models feature an SD card slot. For most users, this means an easy way to transfer digital photos by popping out the memory card and inserting it directly in the MacBook without needing to bother with cables or external card readers. But, that isn't the only advantage.
My first thoughts on seeing this feature Monday were that it would present an alternative to USB flash drives which, while not really big and bulky, are bigger and bulkier than SD cards.
However, Apple's recently published Knowledge Base article on the cards shows that they have some other uses in that they can be used as boot devices for Mac OS X. This gives the slot a lot of advantages as cards can now be used as emergency boot/repair disks, loaded with a copy of Mac OS X and a selection of Mac utility software. This could be a huge space-saver for technicians that currently need to carry either bulky external hard drives or a series of bootable utility DVDs around with them.
Another possibility, not specified in Apple's note that should be possible is that SD cards could be used to boot a MacBook and clone a pre-configured hard drive image onto the machine, which could prove both a viable troubleshooting and deployment solution - particularly for MacBooks in the field without access any form of network-based deployment tools.