The article itself is a total exaggeration. If you book a hotel in
Spain, they will request a credit or
debit card in advance for the reservation. Just as most countries in the world do. On check in, they will also note your passport details. Its unclear yet if they will take a scan, as many other countries do (the UAE for example).
The change now is that if you book a private rental (AirBNB for example) the same info now has to be collected by the private rental owner (card details and passport details). If they pay in advance by bank transfer, they must now keep a record of the bank account the transfer came from. That info is not passed to the Spain government unless requested.
There is no obligation to ask for bank balances, although (just like any country in the world), if you arrive at the Spain border from outside the EEC/Schengen area, Spain
immigration (just like the USA, Canada, Australia etc) has the right to ask you to show evidence that you have sufficient available funds to support yourself during your trip. This is at the discretion of the immigration official.
However if you are not a EEC citizen, from next year you will have to apply in advance for a Visa to visit Europe (just as you do now for the USA, Canada, Australia etc) - and it has not yet been resolved what info the online Visa application will ask for. The visitor will also have to give biometrics on arrival. Not sure it will be any more intrusive than a non-American visiting the USA though!
EEC passport holders (excluding the UK following Brexit) will not have to apply for a visa and do not go through immigration to enter Spain.