Smartphone use is the cause of much YouTube and social media addiction. The cost of engaging in internet-induced addictive behavior is very little, allowing the addicted no time to build rational mechanisms against systems that are designed to retain attention. I do think that most (not all) cases of Facebook, youtube, and pornography addiction can be resolved if people went back to dumbphones, which I like more. It would increase the cost of producing internet-induced addictive behavior. If you use a desktop, you atleast have some time to turn on the UPS, the CPU, and then a browser before you waste time on Youtube. Similarly, a tablet needs to be turned on before you do anything. The point is there should be time between compulsion and the compulsive behavior for the rational mind to process the compulsion. I remember my friend deleted her Instagram because she was wasting too much time on it. Accessing it on a browser increased the cost of her compulsive behavior. It doesn't mean that she couldn't redownload them. It just means that redownloading would take some time, which is enough for the rational brain to catch up and tell her that Instagram is dumb.
Other issues related to smartphone use are eye strain, neck strain, constant exposure to potentially harmful radiations, individual surveillance, data mining, and exposure to personalized propaganda.
As you can see in the video, google shows different results to different people. In this way, smartphones are one step ahead of TV. Via television, you could adapt propaganda only to specific geographic areas. With smartphones, you can tweak it to the individual level. Two people living in the same house can be watching completely different takes on the same event and have contradictory opinions. Smartphones are probably the most effective means of programming, controlling, and monitoring the human mind.