Are Facebreaker any good?

Like we need to deal with unique enemies in the campaign to get damage on them.

I got them when I was in maps already, tried to build around them on my titan.

But the damage is just not good, every rare enemy in level 78 area felt like a literal raid boss and I got like around 600 strength. Near to all gear slots have strength. So I have 120% MORE damage just from strength.

I went for all the damage nodes I could find on tree that make sense with also upping defenses.
At the moment 75% ele resistances 0% chaos resistance cause the gear gets just far to expensive.

I am a bit disappointed in how facebreaker are and how badly they scale. Like shyaba, the unique two hand mace is faster and has more base damage overall, after runegraft upgrades.

Is it anyhow endgame viable or just a complete bait? And if not what kind of crazy gear do I require to actually deal damage with them. I mean for low level maps they were "okish".

Or is it only good in combination with the new OP ascendancy?