Indeed. Nonetheless, that sabotage seems to be a fact. I'd completely forgotten about the story in parent's wikipedia link; the similarities are striking. But in Georgia, they struck Georgian electricity distribution at the same time as pipelines; in the Nordstream attacks, they're not attacking European electricity distribution.

So why blow things up, when you can just turn them off?

Maybe for show. By blowing them up, they demonstrate that they'll never be turned on again. What's that good for? It shows Russia's contempt for the cancellation of NS2, for business with the West in general, and for sanctions. Perhaps it's a muscular display of their power in the field of energy.

How can you show off, if you're going to deny that you did it? Well, it won't be the first time. There has been a number of murders by poisoning recently, just in the UK, that were pretty obviously Russia, that are denied by Russia. But the purpose of those murders was likely meant to intimidate - they needed to be obvious. So I recognize the MO.

I still think it's Biden, based on nothing at all. Except that he more-or-less promised he was going to.

These pipeline explosions ocurred in the "exclusive economic zones" of Sweden and Denmark respectively, so I understand. They are being extremely guarded about their investigation, refusing all requests to observe. Including from Germany, who are part owners. I think that's interesting, given that one early suggestion was that "Sweden done it".