What are the advantages over a "wet" underfloor heating system?

Many! A wet system will cost more to buy, more to install and more to run than the Accolade system. It will also take much longer for a wet system to respond to thermostatic control (anything up to 4 hrs compared to just a few minutes for the Accolade system)

With an electric system you do not require a cupboard full of control valves, and because the electric system is not embedded in concrete or screed, it is easy to access – so in the unlikely event of a fault it is a simple task to source the fault and effect a repair without digging up tons of concrete. It doesn’t leak and as there are no moving parts, there is no costly servicing of the equipment.