Jym's you essentially got it. Pretty much everything goes back to the fundamental theory of poker. We win money when our opponent makes mistakes and (less importantly in this example) when we make as little mistakes as possible. A multitabler will always put us on certain hands UTG, and will always put us on certain hands from CO and OTB. It's like if the board is A9886 facing a river bet from us with AQ, opp may call because they are beating two hands that are in our range, AJ/AT (given the action lets say this is the conclusion they come to). So they call and lose because we never have AJ/AT. You can feel really good about this because we have essentially made money by exploting our opponent.
In the same note they may fold a lot to our two barrels because our range is percieved as much tighter from the LP even though it isnt as tight as it seems.

The reason I said its not really deception is because you have to start thinking of poker as a game of beating your opponents. Deception makes it appear that our opponents are innately good and we need to do something different so they don't read us as well. This isn't true, our opponents suck, we have to figure out in which ways they suck and more importantly figure out how to completely annihilate him because of his specific suckage. Here we exploit the fact that our opponent isn't actually paying attention to how tight we are from each position and instead taking our PFR and VPIP as a range of hands they are just guessing from expereinces with players like us.
And yeah it seems very little, but im sure its something very few of you even considered before reading this thread. Isn't it really cool? Well guess what? There are tons of more elements to the game just like it!

Deception is more one sided. We decieve by playing our hand/s in a different way. With exploitation we can think of more we can do the same thing every time, do a completely predictable strategy, and have it be the best way to play.

If I told you I threebet Kxs, Axs, TT+, and AQ+, most players at 200nl- wouldn't actually understand what they need to do against it. You may not even know right now (although its pretty obvious, fold all A and K high flops, and get it in on low ones) Here I'm employing a completely predictable strategy, not deceptive whatsoever. But this strategy is extremely effective against those who don't know what to do against it. Again, we win because our opponents don't play the way they should if they knew our range.
This is most of poker. It's not what should I do when im c/r all in with AA on a K975 board (In fact, most hands posted on this forum by some of the good players are just super marginal spots that aren't even worth focusing on because of how little the decision will affect your winrate). It's actual poker strategy. Do you here that? most of poker takes place before a decision is even made. It's feeling how your opponent is playing, and figuring out whats the best way to play against it.
The next level of this is very simple. People begin to figure out what you're doing and adjust. at 400nl and 600nl these adjustments are very slow. at 200nl- these adjustments are almost non existant (making poker super easy, in fact, you might as well find a reg who has some big leak and sit to the left of him on 12 tables). at 5/10+, these adjustments happen very quickly.

Sorry sauce for kind of ranting in this thread but i hope it helps.