My guess is that because relatively few people are interested in using them (due to ~90% of Australia's population having cell phones) it means if they charged money and somebody didn't have a phone they'd likely just ask someone to borrow theirs for a second. Plus with VOIP calls are nearly free and they already have an internet uplink right there for the 5G.

I figure the only people that would choose to use them nowadays are likely in some type of "emergency" and can't use their cell - whether it's they left their phone at home, battery is dead, etc.