I do still receive them occasionally, almost always as printed checks from companies.
By this I mean, in the US everyone could use CashApp, Venmo, PayPal, Zelle (glorified ACH, right?), etc. for p2p payment. If you have the same bank, many banks have a trivial "send money to another customer's account" feature. However, to do so requires essentially a 'handshake' where the two parties agree on a method. Checks require no up-front handshake, since everyone knows what to do with a check (deposit it at your ATM, take a picture of it with mobile app, or take it to a check-cashing place or the issuing bank).
If I could print on paper a key or QR code that allows you to claim the money into the account of your choice, like a check does, I'd use that. Sadly, banks seem to have put their effort into Zelle instead.
For all I know, they might even be banned from that app, and unable to sign up to retrieve my payment.
Also, there is less of a need for a receipt when paying by check. If I pay someone by check, my bank has a record of it. If I pay them by cash, I better get (and keep) that receipt in the case of a later non-payment dispute.
It’s not unusual for me to get an invoice for a company via QuickBooks Online, with cash or check as the only payment options.
Other businesses around here have started giving discounts for paying with cash or check versus apps or credit/debit cards, to avoid the recent increases in fees.
I’ll also write checks when having a “hard” traceable payment instrument physically makes sense for auditing purposes or fraud prevention, although that’s less frequently needed.
Of all things my life insurance company is still not set up for credit card payments. In 2023.
Boggles the mind.
Australia/Canada have been doing free bank transfers since before I was old enough to know