It is an interesting idea but also with many flaws.
Basically allows dirty money to be converted to a powerful passport.
Some are just for sake of VISA travel such as the Bahamas or maybe a gateway to US long term visas. Many Russians doing this but it not citizenship though,
Some are buying direct citizenship see Canada and Turkey.
US technically has this type of citizenship too but it is pretty hard to get compared to the two above. About 20% of applicants only get.