I don't doubt that they know what they're doing, but my youthful political activity was always lit distribution. I'm rather good at it, can read people well, and am pretty dang mobile and capable of dealing with pedestrians from multiple directions.
Going out knocking on doors just doesn't feel the same. That said, people with a lot more experience canvasing may feel the same but in reverse.
Oh well, have a lot more money to donate now than I used to.