I'd be curious to see the display connector pinout on my current work-supplied HP laptop (which isn't very repairable at a component level either, although I CAN swap the M.2 SSD and there's ONE swappable memory module (the other is permanently soldered). Or the old one I had, which is one of those big heavy 17" clunkers, very thick and heavy, but you can (and I have) completely disassembled it to component parts. In fact I have a spare screen for it, I can probably see which pins they used for what. But odds are there is SOME low voltage data pin next to the power pins. It may not go directly to the CPU, or to any sort of mux chip (since neither has a discrete GPU) but when the CPU is a directly soldered BGA part, even on those old machines, what real difference does it make? High voltage on a data pin is going to fry something, even if it's not the CPU. But even if it goes to a cheap and easily replaced SMD 74HC something or other logic, it's still got a great chance of damaging the traces as well as the part upstream from the connector. If the board itself is damaged, what does it really matter that the fried chip is a cheap logic gate or the whole CPU? Still need a new board.
Bottom line, don't spill stuff in your laptop, unless you have something like one of those Panasonic Toughbooks that can take it. Don't spill water in your desktop system, either. Could they make a Macbook that's IP67 rated? Surely they can. But it's not, it doesn't claim to be, and if the water gets in there, even if it doesn't hit that connector, something else will get fried. That's not a design flaw if it can;t stand a glass of water being dumped on it, few others can withstand that either.
I wouldn't buy one, I am just not a fan of the OS. Thing is, Windows laptops in the same sort of form factor are just as expensive and resort to the same techniques of soldering in things like the memory and not allowing much if any expansion. And have shitty short throw keys. You want a machine that thin and light, there's a price to pay. Just go up SLIGHTLY on Z height and weight and suddenly everything is user upgradable, and the price comes way down. Apple is far from aloe in building machines like this. Maybe it's because they more or less have just the one model, whereas with someone like Dell or HP, you can get a macbook-style machine, or you cna get ones that are thicker, heavier, and cheaper.