It is a manipulative and misleading indicator. Use it with your own awareness about what it is, and the bias it can distort your thoughts.

Outflow can come from

• New bought bitcoin was withdrawn from exchange wallets to personal wallets (should be cold wallets)
• Old bitcoin was withdrawn from exchanges. By old bitcoin, I meant about bitcoin was bought long time ago (months or years) and was withdrawn out of exchanges recently (just to bias the thoughts of people)