There is always going to be a level of strategy when you play poker. You might not think you're following any strategy, but you are. For every decision you make, there is a strategic reason behind it. Why did you fold this hand? Why did you raise with this one? Why did you call here? Bet here? 3bet here? And so forth.
While adapting-this is a strategy-in poker is good, the poker terms themselves will always meaning. The strategy behind the terms may vary, depending on situations, but the terms will always be the same. UTG will mean the same thing in a cash game or MTT, 6 handed or 9 handed. Terms like 3bet, TAG, LAG, cutoff, hijack, float, range, pot odds
, hand odds, effective stacks, ICM, etc are always going to mean the same thing.
Is it necessary to know all these terms while playing? I think so, especially if you wish you look to improve your game. These are common, widely used terms that make it easier speak, discuss, or type out strategies or a particular hand. So, any time you're watching poker on TV or online, and they're discussing a particular hand, they're going to use this terms frequently-especially from the players-so it'll be good to have an idea of what they're saying.