Tactics are the integral part of the game. Everything you do on the board is centered around tactics. You should practice them as often as you can. Even positional greats like Tigran Petrosian knew of the importance of tactics in chess. Without them, you wouldn't even have the game.
Once you know tactics like the back of your hand, you will know a lot about how chess works.Positional and strategic play must be grounded on sound tactics anyway, so you have to learn them no matter how you look at it.
I figured it's the other way around, without sound positional play tactics don't really exist...
Both are needed. You have to be stong positionally as well as tactically if you want to reach the top. However, even top players only excel in either of these. No one would say that Mikhail Botvinnik was a tactical player, for instance, yet he was still capable of attacking forays into the opponent's position. (In fact, attacking in chess is more of a strategical skill than anything else. You can attack on the basis of general ideas, whereas in defense you have to be specific.)
In general, every player has a certain style; defensive, tactical, positional, etc. However, each style requires a certain amount of knowledge on a tactical and strategical level. Tactics just happen to be a little more basic than positional concepts, and they are also seen more often. You can become a good positional player after you have mastered tactics, but you'll never understand positional chess fully without a thorough knowledge of the said tactics.
spoiler> Thank you, by the way where is he now?
I have no idea what he did after quickly achieving expert as an adult and publishing his training method--certainly nothing of interest to chessplayers.
hehe, I think he went nuts, doing them puzzles...10000000000000 of them