Simply put, yes.
There is only one way to warm up the electric cables in the floors, and that is by running electricity through them. Because the cables provide resistance to the electricity flow, they heat up (just like your kettle does).
The efficiency of this method is around 99% (meaning for every 1.0kW of electrical input, you get 0.99kW of heat output).
Even if you have free PV solar power input, you are still limited to the low efficiency of the heat generation (1.0kW of free solar power = 0.99kW of free heat).
With hydronic heating, the heat can be created by a large number of processes (gas boiler, heat pump, bio-fuels, solar, etc). The heat created is then transferred to the water which runs through your floors.
If we consider a well designed and installed floor heating system with a heat pump as the energy source, the efficiency will be 450%.
This means that for every 1.0W of electrical input, you receive 4.5kW of heat output – meaning that in this situation, the running cost is 4.5 times lower than electrical floor heating… and if you have a PV system, every 1.0kW of free solar power = 4.5kW of free heat.