Very true, very true. That by no means means that using treats is not good however. Most of the effects of behavioral extinction can be overcome by a variable reward schedule, ie giving the treat sometimes but not others. In fact variable reward schedules are somewhat counter-intuitively more effective than continuous reward schedules.
Its what I call the vending-machine/slot-machine issue. No one gets addicted to vending machines, but people DO get addicted to slot machines. Gambling is addictive primarily due to the variance of the reward pay-out. Vending machines pay out much better, but the consistency of it is "boring".
So yes, our praise should be their main reward. But that praise should be, on not rare occasions, associated with treats. However most of this goes without saying as most owners do this naturally without delving into the theory.