Wouldn't it be somewhat valuable as a backup, especially if it has not used it's fuel?
It is useless in it's current orbit. It would use up most, perhaps nearly all, of it's fuel to reach the proper orbit. Depends upon how they do it. If they swing around the moon, there is the possibility of damage, as happen to that AsiaSat. If they could get it up where it's useful, it could be a primary satellite, no need to be a backup. Even if it's only good for a very few years before running out of fuel.
Boeing is (supposedly) demanding payment for them to use Boeing's idea of swinging past the moon to save it. If they just proceed without Boeing approval, Boeing can likely file for a restraining order, dragging it out to where the satellite is useless.
The sat must keep enough fuel onboard to deorbit or reach the graveyard.
Too many uncertainties. They seem to have decided to cut their losses, rather than risk court action and paying people and tracking sites in some attempt to salvage the satellite.
This is bad news for the Russians as well. I'm not sure they can get insurance, or at least, reasonably priced insurance, for any future launch using the Briz (Breeze) upper stage. Too many problems. They will have to be
very convincing that they've fixed the problem before anyone would want to use it again, or insure it again. I suspect they will accelerate the development of the replacement upper stage, which is already well along.