RDM scales badly at 70. You'll end up doing the lowest damage, though not by much and only against equally skilled players. RDM has utility, though it's mostly prog utility. Vercure shouldn't ever be used if you instead can be dpsing. Verraise is more useful and can see use much more, easily saving a group from a mistake. But at the highest tier it's all useless as no one should be messing up. Embolden is always good, but other class have better dps buffs so it's not particularly craved. No class is ever useless.

Impact is being used properly afaik. It's also good to never let an Impact fall off, or at least that's what I'm told, but I let it fall anyway bc I am bad.