ArriveCAN is still in operation. I actually used it myself a couple of weeks ago to return to Canada.
About 300,000 people a month use it, so about 3.6 million people use it. There are big advantages to using ArriveCAN. There are now dedicated lanes at the international airports that operate with ArriveCAN so that you can get to the front of the lanes. It also significantly reduces the transaction time at the primary inspection kiosks.