We should have a mandatory jury system because if we didn't we would have to rely on volunteers, which brings up the problem that we would just keep getting the same people over and over again, which could influence their thoughts on cases.

With a jury we get actual people from the community but if we had to bring in professionals we wouldn't get that. We would get people detached from the case not paying attention.

By following your own logic the human race should get rid of vaccines, modern medicine, all forms of travel and education. We should also get rid of all the prisons on the Earth, because they are expansive to run.

Mobile phones are an absolute need in modern day life, from calling people to doing math phones can do it all. They can help people stay informed on the happenings of the world or help people stay in contact with each other, and considering how wide spread they are you are limiting what you can do, who you can contact and the information you can assess when compared to everyone else.