Pillars make planning faster and the feed coherent. Instead of starting each post from a blank page, you pick a pillar and the question becomes what to say about it this week.
A good pillar names the job as well as the topic. “Recipes” is a topic. “Recipes that show our pasta is made in-house” is a pillar, because you can tell whether a post did its job.
Example
A barbershop's pillars: the craft (cuts and how they are made), the people (barbers and regulars) and booking (free slots and offers).