I guess it could already allow full body transplants for tetraplegic patients... I mean, if they have no muscle control, and get a brain-dead donor, they have nothing to lose and might live who knows how much longer.

Probably a step farther, would be spinal nerve reconstruction, or using stuff like a brain implant to reconnect to the new body. Bridging nerve gaps is one of the first goals, and Neuralink's first human tests are to be performed precisely on tetraplegic patients, so the two might be a good fit.

The article mentions an improved way to maintain blood flow to the isolated part, so that would be beneficial for all surgeries that need isolation (like heart surgery).

Of course the "pump random drugs only to the brain and see how it reacts", is also interesting, just not as sensationalist... and they could even eat the rest of the pig afterwards, if the test drugs don't make it there.

The article does say that, but the source paper the article links to says this in the Abstract:

Thus, we set out to mechanically render cerebral hemodynamics fully regulable to replicate or modify native pig brain perfusion. To this end, blood flow to the head was surgically separated from the systemic circulation and full extracorporeal pulsatile circulatory control (EPCC) was delivered via a modified aorta or brachiocephalic artery. This control relied on a computerized algorithm that maintained, for several hours, blood pressure, flow and pulsatility at near-native values individually measured before EPCC. Continuous electrocorticography and brain depth electrode recordings were used to evaluate brain activity relative to the standard offered by awake human electrocorticography. Under EPCC, this activity remained unaltered or minimally perturbed compared to the native circulation state, as did cerebral oxygenation, pressure, temperature and microscopic structure. Thus, our approach enables the study of neural activity and its circulatory manipulation in independence of most of the rest of the organism.

And nothing whatsoever about physically removing the brain from the body. It's teeechnically separated from the body's circulatory system - with the experimental, artificial connection replacing the natural one between tthe body's circulatory system and the brain's blood flow - but that really seems to be it.

The article is extremely misleading and only barely connected to the actual study, in short.

I'm personally gonna add Popular Mechanics to my internal list of pop sci rags that can't be trusted.

Are you sure? Based on the article, how exactly did they "separate" it?

It's a blood vessel bypass to the whole brain, the BBB is between blood vessels inside the brain and brain tissue.

The implication for drugs, is in drug research: normally a drug will get spread all over the body, particularly passing through the liver, which metabolizes all it can, followed by the kidneys, which piss out all they can... so it isn't easy to estimate how much of a given drug actually gets to the brain.

With a bypass, they can inject drugs directly into the brain, and see how they work without "interference" from the rest of the body.