What does "buy for cash" actually exactly mean?

[Simon Stahl]

When using the phrase "buying for cash", what does that actually exactly mean? Does that mean that person does have the whole amount in their bank account? Or does it mean that person is using a HM lender that can come up with the cash in a short time period? And when you think about it; even when using a conventional loan, the seller still gets cash at the end. It just takes a little bit longer.