It depends on what you want to use it for. Australia currently has polymer currency that means we've basically forgotten about counterfeiting, but before that we had a $100 note that was greyscale with a bare whiff of colour. Not the best design. You'd occasionally hear stories of people who'd simply photocopy the bill on standard paper, scrunch it up to look used, then find a sleepy clerk at a late night convenience store. Buy a couple of bucks worth of stuff, leave with >$95 real change. You'd have to be pretty inattentive to be fooled by it, but, well, humans have foibles...

Counterfeiting is unfortunately still a thing in Australia. A friend who runs a cafe makes his staff subtly attempt to tear any $50 note they take due to counterfeiting in the past.

They were caught out by scammers (or unknowing people with scammed notes) several times last year and the bank rejected the notes (and of course wouldn't hand them back)

Apparently the counterfeit notes are sometimes on a plastic too, but not sturdy enough to withstand a quick tear. I'm not sure how long that will hold true though.

I stand corrected. I knew there was still a little out there, but it sounds like more than I thought. I remember doing retail in my mother's shop in the paper note days and having to be moderately vigilant, and I've not seen retail staff doing any routine sort of note-checking since the start of the polymer days.

People are often successful at passing very, very low quality counterfeit bills.

Absolutely. +jpeg.