Isn't this worse for the US than for Germany? Isn't it in the interest of the USD to keep swift as the primary method for moving money and not let any other system rise?
It only hurts the US if this action leads to the rise of an alternative.
But SWIFT is pretty deeply entrenched in the industry and having other standards compete is a recipe for chaos. Russia's system that they been building since similar threats in 2014 may soften the blow for them, and allow them to continue to function albeit with a lot more difficulty.
BUT: this entire situation with the Ukraine is made possible-- in part-- because Europe has ceded much influence and control over their energy sector to Russian supplies. Europe is restricted in what they can sanction lest Russia retaliate against their energy supply.
Because of this, I very much doubt that many European countries would further tie themselves to Russia with a new Russian-backrd protocol. If anything I think this situation will Europe step back a bit from that relationship. They'd be wise to build out more extensive energy supply infrastructure from Canada and/or the US so that they are diversified against risk of geopolitical conflict. And if course at the same time significantly ramp up home-grown renewable resources to that dependence on any other major foreign powers is kept to a minimum.
As far as I understood, the first order effect is that excluding Russia from swift disables the usual way for Germany to pay for Russian gas and oil, which means that unless they physically move a truckload of euros to Moscow (and get Moscow to agree to that) they are cutting themselves off from one of their major energy supplier. Plus Russia is a big trade partner, but any outstanding bills will then likely go unpaid, and most likely a lot of contracts will be voided.
In Russia they've been preparing for this and were slowly moving to use their inside systems at least for the transactions inside the country. As well as they've been preparing for the moment their internet infrastructure might be cut off from the rest of the world (Cheburnet). It's only delaying the inevitable, Russia was clearly heading for isolating itself from the influence of the west.