Many use just tripwires. I use 2 trip wire rules simply to allow me to draw more wires. You also need to consider direction with trip wires as they're directional.
The function of CPAI is fitration not detection. The cameras software one of the trips, motion etc options or BI motion (one or the other) depending on which system you decide to use does the detection. CPAI just filters the detected objects to prevent false alarms / classify them. If you're happy without AI, then don't use it. The function is simply to stop false alarms as motion will be set off by any motion within the parameters and trips will be set off by anything that crosses. That can mean when eg you're looking soleIy for humans or a certain type of animal, a whole host of animals, wind moverment etc can trigger false alarms. Some cameras have built in AI which can do the filtering effectively.