Going back to the OP's original question. I started commuting on a road bike with 23mm tyres. I do a short commute 5 miles each way. I found it mentally tiring having to dodge every pothole for fear of wrecking a wheel or getting a puncture. I've now got a Marin hybrid with 40mm tyres and though it more phyiscal effort to make progress its less stressful and you don't panic quite so much if you see a pothole at the last moment..
You can also go faster over rough ground.
If you've got a 30 mile commute then you need to compromise as 40mm tyres are going to take it out of you over that distance.