What would reason look like in this case?

Awarding someone billions as an expression of (righteous) outrage.

I like this punishment — the damage has already been done, now he’s going to pay for it.

Of course he isn’t going to have, or ever earn, $1.2B but the court can garnish his wages.

The compensation to the victim will enrich her life to a degree. If the perpetrator was incarcerated all she’d be paid is peace of mind.

There’s nothing in this judgement that is stopping her from getting a permanent restraining order or anything. She may already have one.

In the US, when someone goes to prison, their life goes to serve private corporations by way of slave labor and exploitation or the prison itself, similarly by way of slave labor. This ultimately costs the tax payer around (IIRC) $50k/year.

Similarly, if Steve kills someone in a drunk driving accident and goes to jail for 25 years, the family of the deceased can rest assured that he won’t be on the road any longer but that does little to compensate for the fact that their loved one is gone.

Money doesn’t bring them back but a mother or father having died is going to undoubtedly become a financial drain for 95% of people in the country by way of lost earnings, child care, therapy, lost productivity of survivors, etc etc.

If instead of working for pennies in prison Steve could be barred from driving for life and instead spend his time doing productive work that earns more than $0.25 and pay a hefty sum in restitution to the victims in perpetuity they’d have the peace of mind that he isn’t driving and also have assistance with their loss.

Of course, he has not been tried or had a lawyer let alone been found guilty.

But assuming he did do it. Why would he stop now, fear of another 1.2bn fine?

And if he insanely enough DID have 1.2bn that would be ok then? He could just pay and walk?

Courts spend a fair amount of effort on finding the most similar older sentences and making this sentence sort well with the older ones. That's reason.

In this case, I'd expect the court to look for older harassment cases, stalking, that kind of thing. $1.2B is effectively an infinite sum of money with no jail time and nothing else (AFAICT he's not blocked from living hear her or from using facebook, etc), so it sounds like a corner, not something that sorts well with other harassment/stalking cases.