In either case you have inflated the pot size in a position where you are a significant favourite to win the hand. Loose or bad opponents may call with dominated Aces like A-T or smaller pairs such as pocket Eights.
While those fears are valid, there is usually going to be more value in 3-betting regardless. There’s always a temptation just to call with these two hands because overcards may come down on the flop or you may miss it completely. Two perfect examples are pocket Tens or Ace-Queen. When you begin to think of it in this way, you soon see that there are quite a lot of hands you should be 3-betting with instead of calling. Whenever you 3-bet for value, you are doing it because you think your hand is ahead of the range of hands your opponent has and, in general, you also think they will call that 3-bet with a worse hand.
