there are several functions where blowing a fuse on an NVIDIA die can grant you more access, not less. In a properly secured design, a blown fuse should always induce a more restrictive state, because a blown fuse cannot be unblown in an economically feasible way.

Not really.

If the fuses are for security, sure. But these aren't.

These fuses are for economic extraction. Doing it the way NVIDIA did it is a safety feature: it ensures that blowing a fuse will never destroy economic value -- it will never turn a card that was previously able to do something correctly into a card that can no longer do that thing correctly.

No, that's absolutely not the perspective of the bean counters at hardware companies. The fuses are also for economic security. If someone wants more features, you make sure that they paid for them. You don't give away higher tier SKU functionality for free. There was probably some cost/engineering justification for it, possibly like you say! Maybe too high of yield. This will almost certainly be removed in the next revision, as have all the many other similar cases before it.

For those unaware, product tiers come naturally with IC's, by disabling physical sections of the chip that can't work due to inevitable manufacturing defects. You don't throw defective chips away, you layout in a way where you can physically cut off those defective sections of the chip, with a saw and/or with a fuse, in a way that minimizes lost sales. This works great in the beginning, when your yields are low and you're still dialing in the manufacturing process. But, as yields increase, you might not have enough of the lower tier chips to meet demand. So you, just fuse otherwise good chips. Chips are cheap, after all! New revisions are not cheap, so features/bugs like this can remain around for a while.

In both IC companies I worked for, had around 6 ICs. If you opened any of them up, you would see the exact same die in every one. After a couple years of great yield, you would then find half missing in the lowest tier.

Though if it enables hardware that wasn't enabled because of binning, making the card unstable, can you go back you go back to having a working card?