If you're wealthy enough to consider a flat tax of €100k/year a good deal, there are a number of alternative countries around the world that seem more interesting. If I recall correctly, Monaco next door "only" requires buying a flat at minimum €1.5M and open a local bank account with minimum €500k to become a tax free resident. But the list is rather long of alternative tax havens.
If you really study Monaco you will never go there. I have friends who went there. If you compare the living cost in Monaco with Italy, Monaco will lose. My friends were there working for a bank. After 1 year they asked to return to their native country.
In Monaco you cannot buy a house with a few acres of land. For the price of a Monegask three room flat, you can buy in Italy a seafront villa five times bigger than the flat and with at least 1 ha of land. You can have a swimming pool, which in Monaco is impossible or will cost you millions of euros.
Monaco is propped up with buildings, almost no nature at all. Italy is cheaper, even by paying 100K a year. For that amount you can only rent a small1 room flat in Monaco.
Quality of life in Italy is ten times better than in Monaco.
Worldchampion F1, Max Verstappen lives in Monaco. He has an income (50 million a year) that is multiple times bigger than mine. Yet he lives in a flat, while you can have a villa four times bigger in size, with swimming pool on the border of the mediterranean sea.
In Europe Italy is the cheapest solution, also considering the quality of life, and the distance to my native country where my children live.
Flats in Monaco: successful traders will never go live on100 sqm flats.
Eden Star 78 sqm 2 rooms 4.4 million Euro.
Fontveille 92 sqm 3 rooms 4 million Euro.
Moneghetti 225 sqm 4 rooms 11.5 million Euro.
Patio Palace 209 sqm (living area only 173 sqm, terrace 52 sqm) 4 rooms 7.5 million Euro. These two flat are much smaller than villas in Italy, and have no garden or swimming pool. And the price is more than 4 to 6 times higher than the price you pay in Italy for that villa.
Renting in Monaco for a 3 room flat goes from 15K till 70K a month.