It shouldn't be called a "convenience fee" unless you can opt out of it and pay some other non-convenient way. What if I don't want their version of convenience? Why should I have to pay a convenience fee? Why can't they just roll this into the main price of parking? It's gotten to the point where as soon as I see the word "fee" I assume I'm being ripped off.

Why can't they just roll this into the main price of parking?

Be careful what you ask for. A common ploy for dominating marketplaces (Amazon, Doordash, etc) is to prohibit merchants from offering lower direct prices than what's offered on their platforms. They always say this is to guarantee that you'll get the best prices with them. But that's a twisted way of saying all prices must be at least as high as theirs, and the point, of course, is to remove any incentive for merchants not to use the middleman.

At least in my town you can opt out by paying with coins. So the convenience fee is for not having to carry coins around. For me at least it's worth the trade.

They should just call it what it is, a booking fee.

Nothing inherently wrong with a booking fee if it is transparent.

The direct way to to pay at their kiosks but those often conveniently can never read your card or with lots of dollar coins and quarters.

Reminds me of the early years of ATMs, when banks would charge their customers a fee for the privilege of using a machine instead of a human teller.