Speed is what makes ponies and horses special. Oxen are tougher,easier to harness, but slower. Before the railway, if you wanted to go faster than a man could run, from 3,000BC till 800BC you were pulled by a pony in a chariot. Then the rideable horse appeared. For over 2,500 years the chariot held the land speed record. Sports cars are an urban phenomenon. If you want to impress people, you go where people are, to the cities.
As cities exploded with the Industrial Revolution, communication speed became critical, commerce increased and rapid transit an essential, yes "white van man" had arrived and he drove horses/ponies/mules whatever. Only 1% of driving was carriage driving, coachman style, the vast majority was delivery driving, milkman style.
The Saddlechariot is designed for milkman style, after all Sean Connery is apparently a qualified horse drawn milk float driver, and what is good enough for James Bond, is good enough for me.
Urban driving is just more fun, the people are friendlier, the roads are much safer, and to be honest there is more grass to canter on than with most rural roads. While stooging along Hadrian's wall from Bowness on Solway, Henry and I had a far more social time driving across Carlisle than anywhere else. We are going to start from the other end and drive from Tynemouth, straight through Newcastle to Corbridge letting people have a go on the way. If you see us, come and chat, have a go, whatever.