I remember my father had a checkbook in the 1970's. I never had one, not sure they even exist here anymore (Belgium).
For payments to friends we use bank apps. Usually the receiver generates a QR code for the payment on their phone, which you scan from your bank app, sign with a pincode, and the payment is executed immediately. If you are not near you can also use their account number to transfer money instantly.
I got a cheque book with my first real bank account in 2004, and felt like a real grown up. In the time since, I have written 2 cheques.
However, I have cashed some cheques - a tax refund cheque and a refund for my remaining balance when I closed a utilities account.
They have the advantage, for the sender, that you can discharge your responsibility to offer a refund by sending a letter, rather than having to interact with the other party. Of course these days you could email them a link to a web form.
For payments to friends we use bank apps. Usually the receiver generates a QR code for the payment on their phone, which you scan from your bank app, sign with a pincode, and the payment is executed immediately. If you are not near you can also use their account number to transfer money instantly.