Ballista's scaling is non-existent

And if you ask which one - all of them.

I understand the "fear" of boring totem/ballista builds.

If during the campaign you cannot find decent weapon, you can find yourself placing it every now and then.

But after that it is hard to justify using this "fixed" damage skill. Crossbows with 400+ DPS are selling for 1 exalt.

Crossbows with 650+ are starting to show up...

What is the purpose of this skill, really? Campaign helper or what?