Experiences with electric underfloor storage heating?

Hello,

I am interested in an apartment that is equipped with an electric underfloor storage heating system.
Do I understand correctly that this mentioned heating system is charged with electricity at night? So you have to charge it with electricity every night?
If I turn on the heating at 6 pm every evening and turn it off again at 8 pm, does it then necessarily have to be charged again?
Is it true that you can decide alone which rooms are heated at which times?
I heard from the neighbors that their average consumption is between 15,000 and 17,000 kWh.

What do you think, better to stay away from it?

15,000 x 0.20 / 12 = 250 euros per month

I wouldn't necessarily do it.