Well, he was one of the driving forces behind making computers very(!) affordable for a lot of people. A ZX-81 was actually my very first computer and it really was some kind of beginners drug: You either got hooked and sooner or later got something better or you lost interest quickly and didn't burn much money in the process.
It offered a surprisingly usuable BASIC interpreter which was probably the best part of the deal - apart from the low price which was made possible by choosing the cheapest parts or the fewest components. I'm still wondering why they used a Z80 CPU...

However, I always regarded the ZX-81 more of a learning toy than a computer and of course engineers don't actually *use* the toys they design. As often with engineers there's always a special kind of elitism involved: The belief to be infallible, the belief to be the only one with the correct solution and Sir Clive appears to be no exception.
I consider his statement about memory usage ridiculous as RAM is plentyful and development time scarce. It's only logical that economy prevails in such a case.

take care,
Calibrator