I don't know every country which has it, but I can tell you that it's that way here in Iceland, too. And Finland. Denmark is the only Nordic which doesn't use it.
After Sweden introduced their ban on purchasing sex, violence against sex workers reportedly went up
This is a lie based around this report. The short of it: Since the law passed, the following reports of changes have occurred:
Verbal abuse: +17%
Hair pulling: +167% (but still only a third of those surveyed reported any hair pulling)
Being struck with a fist: -38%
Because when you consider them all together and equal, it's a net increase of 7% (52% to 59%), that's "violence is up". But most of those cases are verbal abuse. The most extreme examples, such as rape, went down by half.
Street prostitution decreased by 50% and indoor prostitution by 16% since the law was passed. The rate of prostitutes seeking help from the police decreased by 41%, but rather than this being some sort of "afraid of the police" situation (they're not legally liable for anything), rates of seeking help from ProSentret decreased by 54% - an even greater amount. The simple fact is, severe violence dramatically decreased since the Nordic Model was adopted.
The estimates on the number of prostitutes operating in Sweden dropped significantly after the law was passed, and are 1/10th the number as in (lower population) Denmark. A study by Durex found that Sweden had the lowest percentage of the population (among 34 countries surveyed) of men paying for sex, at 3%. But as for:
as did the number of "johns" going to Denmark for sex.
Obviously, just on the face of this, this is stupid. The concept that you'll get the same rate of people visiting prostitutes when they can get it where they live vs. where they have to drive for hours (Stockholm to Copenhagen = 10 hours round trip) and pay ~$50 each way to cross the bridge (let alone the super-expensive Nordic gas prices) is nonsense. Furthermore, the rate of people going to Denmark to buy prostitutes has not increased. A large majority of the population in countries with the Nordic model strongly support it, not just "politicians". Only 25% of Swedish men and 7% of Swedish women support repealing it.