It is very common to see an older rod that has loose ferrules, the glue has dried out and failed but the mechanical lock holds it in place. I don't see any downside to pinning ferrules when done properly. The pin is barely visible and the ferrule is locked, but is it necessary? The choice is personal, think of it as insurance. You don't need it until you need it. A well fit ferrule with modern adhesives should last a long time and a pin is not required. If you sell rods a pin is nice because the owner may not be as careful as you removing ferrules and will be very disappointed if, while fishing, the ferrule pops off and a days fishing is ruined.
Whatever you choose there is no right or wrong, a simple hand drill with a fine drill will prove a challenge but a small vise and drill press or stand will get the job done.