Tipping is only realistically possible with cash!

The option of giving small amount of money to another person, call it "tipping" or "Tzdaka" or anything else is realistically possible only with cash. Cashless will increase the amount of suffering by removing this valuable ability.

Giving a penny to a homeless person.

In Sweden homeless people were given credit card machines so they could still receive their pennies. Which is not the best system in the world.

For this machine to work, the homeless person should already have a bank account and a credit card, to later use this money. If the cause of homelessness was, say inability to pay up the credit fees. Meaning the person is in very large debt in the bank. You giving that person money, by swiping your card, will not give them food, or anything that they might need urgently now, but rather it will lessen their dept by a few pennies, that will probably be taken away from him anyway for bank's operational cost. With cash it doesn't happen.

And this is if that person is eligible for a bank account in the first place. Many refugees cannot get a bank account and end up on the streets with nothing to eat. Those will have no account to connect to this device, even if government will somehow give them one. And no card later to use.

But perhaps the government knows all this. And just tries to kill off the homeless since they look bad and scare off tourists, that bring in the money.

Tipping a waiter

A lot of service work, is being paid so low that they are pretty much relying on tips from customers. Companies get away with this by either hiring teenagers who's minimal wages are way lower than those of adults ( which is a problem in itself that has to be solved separately ) or minimizing hours that those waiter work, so to pay them as little as they possibly can.

Even with cash tips, a lot of those places require the workers to report every tip so that the tips could be spread among the workers. Which is done by managers, who can rig the system and deprive the workers from most of their tips.

With cash, a worker who received a tip relatively secretly can not report it and therefor live a slightly less painful life. If, for example, they would let you tip them with a credit card, the managers could still deprive workers from their tips. Which is not solving anything.