We mail some postcards, but keep struggling with lob's pricing. We order postcards for ~3 cents and can mail them for ~30 cents.
Overall, this is about 1/3 (33 vs. 94 cents) the cost not including our time. It takes us about 20 sec write down the address therefore saving ~$1.80/min so ~$100/hr. We drive by a post office everyday so it isn't much trouble to mail them.
I guess the target market is those that have people filling out postcards for greater than $100/hr?