Wouldn't places with good conditions for solar heating generally not need the underfloor heating for the season when the solar heating is most effective?
This has been my impression, and why solar heating is most useful for heating water.
The question is: is it efficient enough during the cold season? Cyprus, situated in the middle of the Mediterranean heat reservoir and with plenty of daylight during the off season seems to be well situated.
As for the need: I'm from up north, our houses are built to keep heat inside as that is most positive for our energy consumption. In the south, houses try to limit the need for cooling. The effect of which became very clear to me when I went to the Mediterranean in November. Heating? Yea please.