Ok, so maybe there is dangerous sparky stuff that can be reached in there - but it just shows poor design that they weren’t able to incorporate a frunk and/or isolate/insulate those components to not make opening the hood deathly dangerous.
But... why?
From the article, there is literally nothing under there that is "user servicable"--everything requires the HV system be placed in servicing mode first: HVDC inverters/converters and the motors. All user-serviceable components (e.g., fluid fill) are located elsewhere.
Basically every vehicle design process is about value engineering. Who wants to pay extra for a car with extra safety features in a compartment that they will never open, have no reason to open, and can't do anything with once they open it?
Whether that's the hood of the car or somewhere else seems immaterial?
(Disclaimer: I work for Mercedes-Benz.)
Every other manufacturer in the world has hot pipes & spinning fans & hand-grabbing belts under the hood with little done to prevent personal injury and it has worked fine for decades.
The EV market just wants everything to 'trend Tesla', so they expect a 'frunk' and for everything to be totally unlike any other ICE car on the road.
You need at least some space in front of the console, because the wheel wells need to be forward of the cockpit so the front seat occupants have a place to put their feet. Traditionally you put the engine there, because it was an obvious empty spot. Cars that didn't generally made significant tradeoffs (like two seats) to accomodate a different engine placement.
But if you've got no engine, what can go there? Not the battery, that works much (much) better as a flat planar thing at the very bottom of the frame. You can put the motor there, sure, but an electric motor is tiny. Add in the random electronics and wiper fluid and whatnot and you still have a ton of space.
So you make it cargo. It works great. EVs that don't have a frunk (the ID.4, ahem) end up feeling like they're missing a feature.
My Model Y frunk is where I keep a variety of charging cables, adapters, extension cords, tools etc so I can charge from just about any source of electricity on long road trips. Plus a tire inflator, windshield squeegee, and a portable 12v Li-Ion jumper box (so I can help other cars and it's also very handy when camping).
All that fits in my frunk with a bit of room to spare.
I guess everyone's different. To us it was a revelation.
See this pic: https://twitter.com/model3owners/status/891361384658763777 and note that it is shallower up front - that bag is just a few inches tall and it is nearly level with the latch.
The fact that the shape is irregular, and the hood metal is so thin, also increases the chance you will accidentally bend the hood by trying to close it on an object that doesn't fit.
Yes, if you decide that you absolutely must put something in the frunk, you certainly can. It obviously has a non-zero volume. But in all circumstances I found it more convenient to put things in the rear trunk, the rear footwells, or the (super useful) storage area under the rear trunk floor.
I thought the Model 3 was a fantastic car by the way. I loved it. I just thought the frunk was a useless novelty.
(The frunk in my Porsche Boxster, on the other hand, is deep and rectangular and very useful, in part because the engine is in the rear).