And yes a handheld (incident in my case) can add extra time but having an objective measurement to train myself against and match my tools to provided a huge improvement in my exposure setting skill.
It allowed me to understand how each meter saw things, and more importantly, how they got fooled. The incident meter allowed me to "calibrate" my system across all my camera meters. In essence I learned how I had to use each meter to match the reading given by the incident meter and how to judge many situations without a meter.
Still and yet and probably always, for situations I view as truly important, I whip out the incident meter.