When a seller of property of significant value or even an expensive exotic car requires a "cash purchase", possibly amounting to millions, is that actual cash - meaning buyers are hauling around suitcases of stacks of $100 bills, or is it just a euphemism for a bank/cashiers check? One of the reasons I ask this is because even a bank/cashier check is not really cash - it's near-cash - it still has to clear, which is 1-2 days depending on the time of day it's deposited, and if it's a genuine check at that.
It depends heavily on the context and on the actual seller. However, in common usage such as for real estate, the term cash is used in contrast to finance/credit.
The following quote and the parallel concepts in the article's title illustrate this (emphasis, mine):
But there’s a lot to consider when contemplating purchasing a home outright versus financing it. - Buying a home: Cash versus mortgage
In Australia, bank cheques are commonly used to settle cash offers for real estate. Although legal tender is as its name says, it would be very unusual to find a real estate buyer ponying up with suitcases full of money.
The phrase cash transaction is all about perspective. At least in the United Sates.
For a home seller, a cash transaction means that the buyer isn't getting a mortgage. That means that the timeline between signing the contract and the settlement date can be very quick. It might still take a week or two, but there is no fear that a lender will slowdown the process. On the actual day of settlement it doesn't matter to the seller if there is a mortgage or not. The money is being sent to payoff the old mortgage using a check or wire transfer. The seller will still need representation so that they can make sure the buyers check is still good. The buyer doesn't show up with a suitcase full of cash.
For the seller of a car a cash transaction is again one in which there is no lender involved. But in the case of an auto dealership they also view a transaction as a cash transaction if the buyer is using an outside lender. If the buyer has already obtained the loan from their bank, the dealer knows that they will get all their money in the next few days, instead of it being spread over a few years. The transaction becomes so much easier. The buyer usually brings the cashiers check in a business day.
If a buyer showed up with a pile of actual money, then there is additional paperwork that needs to be filled out. The US government wants to know where all this cash came from.