(A) Definition: Arc-Fault Circuit Interrupter. An arc-fault circuit interrupter is a device intended to provide protection from the effects of arc faults by recognizing characteristics unique to arcing and by functioning to de-energize the circuit when an arc fault is detected.
NEC Article 100-Definitions
Ground-Fault Circuit Interrupter (GFCI). A device intended for the protection of personnel that functions to de-energize a circuit or portion thereof within an established period of time when a current to ground exceeds the values established for a Class A device.
FPN: Class A ground-fault circuit interrupters trip when the current to ground has a value in the range of 4 mA to 6 mA. For further information, see UL 943, Standard for Ground-Fault Circuit Interrupters.
As you can see, by definition, they perform different roles in circuit protection.
The GFCI is primarily for personnel protection and is designed to de-energize a circuit at low ground fault levels. Low enough to prevent burns or electrocution for any person unlucky enough to get into a position to receive a shock from one of the ungrounded or hot conductors to ground.
GFCI protection is required in several areas in a residence, including outdoors, kitchens, bathrooms, unfinished basements, garages, etc. GFCI protection may be built in to a circuit breaker or a receptacle.
AFCI detects arcing faults, such as could be caused by damage to a cable. Arcing faults may be at a low magnitude, low enough that they would not exceed the circuit protection of a standard circuit breaker of fuse. An AFCI will detect low magnitude faults and will de-energize the circuit before a fire starts.
At present, AFC protection is only required for circuits supplying outlets in bedrooms. Outlets include both receptacles and lighting outlets.
At this time AFCI protection is only available in circuit breakers
as you can see here arc fault interrupters are designed to protect property not people gfci are, if your relying on an AFI to save your life you have faith in the wrong product, this is a deadly serious issue, it is important to make sure you have the right product for the application.