That's not relevant. The point is to show that consequences have actions. Otherwise, any president can try to incite insurrection in their final days, with the gambit that if they fail, they won't be prosecuted. That's a terrible precedent. It would allow any president to basically try to extend their term by inciting violence, with no consequences. They either stage a successful coup, or get off scot-free.
Dems are correct to pursue this, even with the knowledge that the Reps won't convict. It's the principle that matters. In addition to that, it gets Reps on the record of which side of the issue they stand on. Given the way polling has gone post-insurrection, it plays into the hands of candidates looking to primary or challenge conservative senators in the coming years. "This man/woman supported Trump's insurrection." Given that this is the 2nd impeachment, and that there's a chance even more dirt comes out via Biden's administration, it could put some balls in blenders come midterms.
On top of that, the people who made the effort to get Biden elected don't want to see the party roll over and expose its belly again. Keep hammering home how corrupt and vile the last administration was, and let those willing to go down with the ship do so.
