I am not one of those "throw the book at her" + "punish the wicked" loons, but I think in her case specifically there are more complexities that go beyond the crime SHE specifically committed.
While in a void I'd agree that jail time wouldn't be necessary for her rehabilitation as an individual, this incident didn't occur in a void.
She is a minor F-list celebrity with celebrity aspirations. Since the incident her infamy became worldwide topic of discussion (the whole playboy bunny looks have a lot to do with that one), and while in court she has said all the right things, in the greater scheme of things she has not really shown any real remorse, on the contrary she seems to have exploited her 15 minutes of infamy.
Allowing her to profit from the crime does not send the right message, nor does it ultimately give real incentives for her to change as a person (still I doubt she personally would repeat this stunt). It sort of says to all the celebrity wannabes (and the various "ice cream licking" and Tide Pod challenges have proven there are plenty of those) that doing dumb shit like this can actually get them the fame/attention they crave.
Now I don't think she should be publicly drawn and quartered to set an example or whatnot, but the judge should have imposed much harder probation conditions, such as restrictions on social media use, ban on giving interviews, TV or media appearances for a couple of years.
That would go a long way in nipping her budding rap/model/reality TV/Instagram influencer/porn star career and would send the message that "This is not how you become famous" message to those who might see her as an example to follow.