Plus campaigning involves a lot of literal legwork. I have family who were involved in local politics (in the UK), enough that I’ve seen some of the behind the scenes of electoral strategy and I was surprised at how much it comes down to just sheer number of people campaigning. Door-knocking especially was valuable in gathering data and helping to figure out whether to bring in national campaigning resources (which usually came in the form of greater press coverage and a high profile person to come and campaign, because they can drum up a much larger group of volunteers — even this targeted support was mediated via volunteer labour)