Or maybe they do have to be there, but they aren't paying attention? It isn't a given that people will pay attention if they need to, that is the whole point.
There are lots of reasons someone might be in a meeting. They might be there to receive certain information. They might be there because they're going to be assigned work as a result of it. They might be there because hearing the actual conversation with the client is useful for being able to understand the context of the work. Getting that third hand from someone that didn't talk to the client is nowhere near as good. That is what leads to wasting time and money doing work nobody wanted.
Sometimes people just don't pay attention when they should. That is real. It is not sensible to immediately assume they're justified in not paying attention. Even if you aren't needed and you aren't interested, it is your job. You are paid good money to be there. Your contract requires you to follow lawful instructions from your employer. Do the job properly and look at your phone at lunchtime. You don't have the right to switch off and start playing with your phone because you are a bit bored and have the attention span of a teenager brought up on Tiktok.
