I get what you’re saying. And yes this could be a sign of water coming in. Yes, efflorescence comes predominantly from water intrusion, but can also come from condensation between the brick and interior walls or even just condensation forming in the basement. If you have any reservations, I would maybe look at a different place. If it is bad, or on its way to becoming bad, this is not an insubstantial repair. Will likely cost upwards of $40-100k to actually fix. But this isn’t because they are brick. A brick or block foundation isn’t inherently bad. Bad work is bad.