Have ceramic coating on all three of our cars, professionally applied. It makes washing the cars much simpler, but it's not a magic bullet, road grime will still build up and you need a "top up" every couple of years, depending on use, etc. It's excellent for protecting from bird poo and other acidic contaminants which would damage paint otherwise.
Gtechniq is a very good brand, but they all offer different products aimed at either home or professional users. The difference is that the home stuff is easy to apply, but doesn't last as long or perform as well. The pro stuff requires skill and time as it's applied very slowly in small patches as if it drips it solidifies with streaks. They sell the pro stuff only to accredited shops, so the £700 sounds about right as it's usually a day's work. It comes in tiny bottles and you get a warranty package. Usually the mobile detailers who offer it for £200 use the lesser stuff, which I think is also fair, but you can do it yourself and it needs to be topped up more frequently, so it seems like false economy to me.
Anyhow, yes, regular washing, polishing and waxing will provide similar protection, but when I did the maths, good quality waxes and my time would cost me far more over two years.