You're both right, but are coming at this from different directions. In the past a rainbow table was intended to reveal as many passwords on a system as possibl

You're both right, but are coming at this from different directions. In the past a rainbow table was intended to reveal as many passwords on a system as possible once you got a copy of the passwords. If one of them happened to be a high-value account, great. But maybe access to an ordinary account is good enough for their (nefarious) purposes. It's also possible to build a rainbow table when you already know an account is high-value and have the salt. You can't go download that rainbow table - you'll have to compute it yourself, so the cost to the attacker is higher. But if the account is valuable enough to justify targeting specifically, you'll do it.