I have had to shell out for a real one and gt to heat it.
So no, they won't do much for insulation!
We liked the Obi products and prices so we took advantage of their offer of free bathroom planning. We booked a one hour appointment and there had a good discussion which actually ran to one and a half hours. They sent us a detailed estimate including everything we would need.
They were also supposed to send us a 3D picture of how our bathroom would look. After a month this has still not arrived despite some reminders, they say it is a technical glitch.
Obi also gave us the names of three people who could do the installation in Switzerland. We phoned them and one was not interested another now only does tiling. The third was a Swiss guy who visited us the same day we phoned, measured up our bathroom and promised to give a written estimate. It is a month later and no estimate has arrived.
Now I have ordered a new toilet and cistern (the sanitärmodule type) from Bernstein and plan to install myself. It seems simple as they have detailed instructions including an English version.
Next steps after that are still open/undecided.
Saw someone spent an eyewatering 25k and yet tiled on existing tiles
Laying backer board will make your surface sturdy and ready to take on the tiles. It should be a no brainer and taking a chisel and breaking the old tiles will take you a day with the backer board covering any potential issues underneath the existing tiles. Even for the flats am doing up for sale in London at the moment I am using backer board by respect to the future buyer. Who knows how the old tiles were laid as well! Tiles on concrete might be the only time where I might be ok without backer board, but then need to make sure the concrete has no potential moisture issues etc... that needs special care. I don't even tile or am a professional, but that just sounds like common sense.
For OP. The initial quote sounds like a F. U. quote. You get those when trades people are particularly busy and have a full order book. They don't want the job, but there is a price at which they'll do it, which is the quote they gave you IMO.
I am not a Swiss nor have I done work in this country. Just bought a house in Geneva and will start demolishing it and trying to figure out the system so I've started my learning process. This type of threads is extremely useful for me to start understanding the landscape.
An extra 10k to put new tiles on a bathroom floor... Now I absolutely understand the motivation about laying on old tile. Ignore my previous comment, I'd do the same if I had to cough out that much.
We did a partial renovation of 2 bathrooms using a local Swiss plumber. We had a lot of issues with the quality of the work. When we chose to add another bathroom we used a different plumber and arranged all the tradespeople ourselves. I found the tiles I liked and bought them directly as they were on sale. Same with the glass shower cabinet. It was a hassle as you have to carefully coordinate who does what when but the final result was really nice and worth the aggravation. We were living very close to the German border at the time but we used all Swiss tradespeople. All the names initially given to me by Obi were totally unreliable. Never showed up for a quote and complained about where we were located.