The first advantage that medical alert systems have over cell phones is their convenience.
They can be worn on the wrist like a watch, or hung around the neck; either being a better place than in a pocket, which can easily become inaccessible should someone fall awkwardly.
They also lightweight and compact, even more so than the smallest of cell phones.
Then, they are more robust and, unlike with a cell phone, dropping one will not cause any damage.
They can even be taken in the shower, or worn whilst having a bath, as they are completely waterproof.
The manufacturers of them have so much faith in their products that a long-term guarantee is standard.
The size of cell phone buttons is another problem, as they are extremely small, which means those with poor eyesight, or unstable hands, can have real difficulties pressing the right ones.
Compare that to a medical alert system, which has just a single large, easy to press button, which needs to only be pressed only once for a direct line of communication to be opened with a health care specialist.
The medical technicians that answer the calls of the users of medical alert systems are trained not only in all kinds of first aid skills, but also on how to deal with a wide range of emergencies.
Unlike those who answer 911 calls, who must process callers as quickly as is reasonably possible, so that they can deal with the next person, the medical professionals who answer medical alert system calls will stay on the line as long as the caller needs them to.