Road bikes are OK, but consider these unique needs of a commuter bicycle:

1. Flats are important to avoid because of time constraints.
2. The need for speed takes a back seat to comfort and reducing heat buildup (sweat causes stinkiness).
3. You may need to sometimes go on terrain that requires more than a skinny road bike tire.

A cyclocross bike running tubeless with sealant fulfills all of these needs. It's just a road bike that takes bigger tires. Using 35mm or bigger tires, you can go 40 psi so sealant works well and the ride is very comfortable over rough roads.