As you said yourself: CHF is not really viable to counterfait, as it super secure. They have dozens of security features + they change all 12-15 years (new ones will be coming 2031, current ones are valid since 2016). Which means you'll have to try ho keep up with whatever the SNB is cooking with their security standard. As far as I know the USD stays the samenover the years.
Also to carry around CHF 1000 and not be suspiscious you'd have to be in Switzerland everywhere else and they'll be checking that money to allnof the security features. Even in Switzerland they check if you pay with it. While USD 100 is super unsuspicious.
You also mentioned CHF is the save haeven currency. Meaning people exchange their money to CHF to save these CHF. They don't buy the CHF to spend it. They buy it to keep in in their saves. So why would anyone counterfit money people don't use? Meanwhile the USD, is the trade currency. Meaning people buy the USD to spend it, so it's easier to use that money.
When counterfitting the money the most important part is the washingbof the money => making the fake money to real money. When are you really going to pay something with CHF 1000? At most you go to a bank and deposit it. Meanwhile with USD100 you can use it and exchange it for real money anytime. No one would care.
Merz really preparing everything neatly for the AFD to take over.