well, apparently AFCi misses many actual faults because the signal of them is too similar to other normal situations... but the arc faults all create heat at the fault... and most are at the receptacle, or switch, except for those that occur due to improper installation of staples on NM cable and other such cables...
So, in the type of installs that I am mostly involved in, that use conduits, I can rule out NM cables being compressed under staples, thus at least for me, most Arc Faults will be involving loose wires at receptacles and switches, or will involve no bushing situations that damage the wires or improper stripping of insulation... all of which make my tracking down problems a whole heck of a lot easier than what the average North American electrician will need to look for. Thus, the idea makes a bit more sense for installs like mine, but, I can also see signs of problems by using a heat camera to look at the wires as well...
But, in other areas where more NM wires are installed, like in wood frame buildings, there are more cases of cable failure that causes arc fault, due to the staples being overdriven. Or missed strikes of the hammer bruising the cable. All of which are shown in the various reports. This is why it was suggested in a few reports that I saw that one could use AFCI at the breaker box and put GFCI after that, at the first outlet... possibly even using AFCI to cover several circuits much as a surge protector does, rather than needing put on each individual circuit, but the panel manufacturers do not want to do it that way.
