[gargravarr]

Not just the risk of data loss, but the inconvenience of restoring the machine is much higher. This means the only solution to restoring a modern Mac notebook is to replace the entire logic board - everything else may be functional except the storage, which is a consumable by most considerations, but now the entire board must be swapped. And if it's out of warranty, which let's face it, it's extremely likely to be, then you are completely and utterly stuck. You either have an enormous bill from Apple or an authorised repair shop (and Apple is notoriously cagey about allowing third parties access to their replacement parts) or you have to hunt down a machine for spares to do the swap yourself, and now with Apple's invasive security measures requiring communication with Apple's diagnostic tools to perform certain swaps, storage failure can render the machine entirely useless for months, if not permanently. Whereas if the disk was replaceable, just order one from the most convenient store, swap it in, restore from Time Machine.

The Function Key MBPs have a problem with their flash storage where they may randomly and unpredictably die, taking all the data with them. The fix is a firmware update, which also takes all the data with it. Fantastic, Apple, we bought six of those machines, and because the users are actively, y'know, using the damned things, it's not really convenient to tell them they'll be without their machine for a week while the service centre gets around to it, and then multiple hours of restoring their Time Machine backups. On the plus side, the SSDs in those machines are not soldered. Yes, they're proprietary, but it's something - if those machines suffer failure, I could grab an SSD on eBay and get them running again. It's almost worth the risk.