I haven't had a use for anything smaller than a 28 for years, but this spring I've found a personal need for them.
I'm a recovering fixed gear addict, which has ruined my left hip. After taking 1.5yrs off of riding any fixed due to my leg no longer staying in the socket, I bought 2 track bikes this spring that I knew I had to ride. I'm cautiously riding once a week or so and not having too much trouble. When I ride my tracklocross rig with a 32c rear tire, I start having that burning sooner. I think it boils down to the lighter rotating mass with the smaller tire makes the regular acceleration/deceleration less Plus if I do accidentally skip or skid, there's so much less tire contact patch.