Key fobs are very convenient for alarm systems since you can activate and deactivate the alarm as you're approaching the home instead of waiting to get to an alarm panel. If the system works on a panel-only basis, you have to rush out of the house once the alarm is set to avoid a false alarm and hurry inside to deactivate the alarm in a few seconds, which is an issue the fob takes care of. The fob is also easy to use, so even a child can turn the alarm off and on as needed which can help keep your home secure.
Most fobs operate on a single button-press, which means your system could be activated in a second. If the fob also has instant-alert buttons on it, you can quickly notify police and paramedics in the event of an emergency. This is especially handy if the alarm is turned off and you realize an intruder is in the house. A fob-less system would require you to find the nearest control panel, possibly bringing you right to the intruder in the process. Since fobs are portable, you can save time and effort by activating the system and notifying authorities from your current location in the home.
One risk of a one-button alarm activation system is the increased odds of an accidental activation or false alarm. If the fob is in your pocket, a key or the fabric of your pants could press against a button and result in the alarm activating. If your fob has a one-button option for emergency services, the risk is compounded because you could then inadvertently contact the local police or fire department. Fines will be levied against you in the event of multiple false alarm activations.
Fobs are also very small and while that makes them more convenient, they are also easier to lose. A fob can easily slip out of a hole in the pocket or be placed somewhere and then forgotten. If the fob is lost outside of the house, someone else could get access to your home alarm. Notify the alarm company as soon as you notice a fob is missing and then contact them again if it is later recovered to keep your system as secure as possible.