Most of the time it is genuinely about the seller
That is worth saying clearly, because the phrase attracts suspicion it usually does not deserve. A seller who has already closed on somewhere else has a real and expensive reason to move quickly that has nothing to do with the condition of what they are leaving.
In that version you are buying an ordinary house from someone with a deadline, and the deadline is the opportunity.
The version worth checking
The other version is a house that has been on the market a while and is now being repositioned on price rather than on repair. That is not deception either, but it is a different purchase.
The question that separates them: how long has it been listed, and has the price moved? A house priced to sell on day one is a timeline. A house priced to sell after ninety days and two reductions is telling you the market has already looked at it and declined, and it is worth knowing what the market saw.
Do not let urgency compress the checks
The practical risk in a fast sale is not the price. It is that speed is used to shorten the conditions, and the conditions are the only place a buyer has any leverage.
The three things worth more than everything else combined are the ones a photograph cannot show and that cost five figures to put right: the panel, the supply plumbing and the roof. None of them takes long to look at, and a genuinely motivated seller has no reason to object to four photographs.