Ah liquid metal. I did so much research on it when I was trying to get my gaming laptop temperatures down. I can see why Sony went down this path as it can bring temperatures down 15-20 degrees more compared to other thermal pastes.
In the end I opted to just turn off turbo boost and under volt the CPU as the biggest concern was that it would leak everywhere. The leaking wouldn't happen when sitting on a desk but rather form me taking it around in my backpack whilst traveling.
There is merit in going down the liquid metal path in future laptop designs, but it needs to be absolutely leak proof long term.