I use checks for a few bills and thats it. City of Sapulpa charges a $5.00 convenience fee to pay online and so I write them a check and mail it for the 50 cents or so it costs. Car payment also charges an online convenience fee so they get a check. Other than that, not much.
The City of Moore and OEC (Oklahoma Electrical COOP) both have an online bill payment service that charges a convenience fee. I just send them a payment via my bank account and they accept it. When I first started paying them in this method, the bank would mail them a payment in the form of a check. But over time, both have created some electronic transfer that gets used instead.
I did stumble upon an advantage of the online checks vs written checks. I was paying my home owner association dues via an online check. It gets sent to their PO Box and they claim they never saw it. They never had problems with the other payments I had sent with the same method via the same PO Box. So I go online to stop payment on the check and see the outrageous stop payment fee. I went ahead and stopped payment on the check to recover at least part of my money and sent them another payment. I followed up with my bank to complain that a large stop payment fee on an online payment was ridiculous. They said that they did not have a stop payment fee on their online checks and refunded my fees. They said they simply void an online check 10 days after sending if it is not submitted for payment.