(and obviously, seller wanted cash) (and it is possible that I misunderstood something)
And I would do the same - just to avoid worrying that maybe transfer is not going to arrive or get reverted or something (that is 100% hypothetical, I do own any housing).
So I am mildly unhappy that it gets outlawed.
In the real (non-criminal) world you would have a conveyancing solicitor handle it, and he would take care of the contract, the transfer, checking for liens, stamp duty etc.
How do you even know the seller owns the flat when you do everything in cash?
I expect that they also checked at least basic status of that property and that it had no mortgage, encumbrances etc recorded in the land register.
I bet that bank also recorded that transactions.
It would have worked just as well in you example transaction where both parties were in a bank. In my example it worked by exchanging this piece of paper while at the notary.
(This is my understanding on how most of the house sales work in Italy)
Doesn't make sense unless you've worded what happened incorrectly by accident.
I would be really anxious if I would be selling something worth 80% of my wealth.
Maybe the entire thing was hilariously pointless? But neither buyer nor seller was expert on this stuff.
(unless seller was hiding really well and it was some 6D chess)