Could using apps be an obsessive/compulsive behavior?

Not likely: Only if people have intrusive & inappropriate thoughts about the app that cause a lot of distress, and then go on to do some repetitive behavior in response to the obsession in order to prevent or reduce the distress. It's more likely that people could develop a habit of using apps--maybe even a high-frequency-use habit. High frequency behaviors are ok unless they cause problems in life.