What about people who have not yet established enough credit to qualify for a credit card?
I once had a check refused because I didn't have a credit card to back up it.
What if your credit card gets damaged and you have to resort to cash?
What if your credit card account gets frozen because someone hacked it and you have to resort to cash?
How many people do you know that carry their checkbook around with them. If something goes wrong with your credit card on the spot you almost always have to resort to cash.

No merchant will take a check in New York City.

I had to buy my Sri Lankan visa with US dollars. They don’t accept any other form of payment or currency. I believe several countries are like that. The neighborhood ice cream truck only takes cash, I believe. Farmers market vendors may or may not take card or check.

There are plenty of small stores and small restaurants in big cities which accept cash only.

Strippers get ruffled if you are stuffing checks and money orders in their thongs! ?

I'm with you all the way. Probably take a whole lot of years to get God off our currency but worth the fight. If you don't fight to change something then nothing will ever change.

I saw a poster in a bar that said 'In God we trust. All others pay cash"

Maybe you can find current plaintiffs with current or prior instances of credit card fraud to show they have been defrauded and can only use cash. Or others that have real bad credit and due to current laws that let credit card companies charge outrageous fees and rates, can’t get credit cards.

Seems like a weak argument. And one that seems unnecessary for the argument pertaining to the establishment clause.

Having said that, I will add that not everyone has a bank account and credit cards. This usually is more true for people at the lower economic scale; certainly those living below the poverty line, but probably even some above it. Plus, not all businesses will take checks or credit cards. Chief among these are probably small local businesses. And what about yardsales and flea markets? What about a lemonade stand?

The court's saying that there are alternatives to cash seems to me to then make it mandatory for the federal government to make certain that non-cash transactions can be completed in all cases. This is a matter of ubiquitous alternative non-cash payment methods, not alternatives to which businesses one chooses to use.

My cleaning person wants cash. Tipping bartenders! The tip jar on a performer's piano top (or sidewalk).

My yard guy only takes cash....
The vendors at farmer's markets generally only take cash
yard sales/garage sales only take cash
purchases from private sellers off apps like LetGo, OfferUP, and craigslist only take cash

we have a local Chinese Take-out place that is "cash only" and has the best prices because of that.

Private parties are not generally set up to take credit cards nor equipped to prevent check fraud.

I'm not a US resident, so not able to provide any instances but I do have one thought. Why not strike through the word "God" on notes that pass through your hands? If this were made into a campaign, with hundreds, or even thousands, participating then pretty soon there would be a high number of amended notes in circulation. I don't know if this is illegal, but with notes constantly changing hands it would be pretty hard to prove authorship and would serve as a very visible advertisement that plenty of people reject the idea that religion and government should be mixed.

In Laos, if you pay in any currency but US (cash only), they penalize you by charging you more for your visa.