As a former Immo 2 player and now aspiring pro I'll give my honest opinion on which sensitivity is better.
Low Sens
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Low sensitivity is proven to be more consistent and gives you complete control of your mouse movements.
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Ideal for arm users with slight micro adjustments made with the wrist.
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Good for low elo players to learn crosshair placement as it forces you to have good positioning because you cannot turn or flick as fast.
High Sens
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Many wrist aimers use this sensitivity as they feel comfortable using their wrist for both aiming and micro adjustments.
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High risk of inconsistency due to over flicking
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Highlight plays and flicks is one of the reasons a high sensitivity is ideal especially if you're good with tracking the opponent without moving your crosshair too much.
Overall, low sensitivity in tactical shooters are just better but personally it took me a while to go from just wrist aiming at 0.90 to now playing both wrist and slight arm at 0.14 1600 dpi.
TLDR: Consistency and competitive gameplay, low sensitivity and content creation + casual gameplay, high sens.