Recently, I saw someone say that when stablecoins supply rises, it's because "off-chain funds are coming back, ETFs are also attracting," essentially confusing correlation with causation.

An increase in stablecoins might just be market makers rebalancing, cross-chain arbitrage, or even project teams locking and unlocking funds to make their books look good; once the narrative shifts, TVL can seem like magic.
ETFs tend to be more of a slow variable, with net inflows and outflows often not synchronized with on-chain activity; don’t just overlay these two curves and start imagining stories.
Airdrop season is also quite funny—task platforms turning from anti-witch-hunting to KPI points, grabbing tokens like clocking in for work; an increase in supply doesn’t necessarily mean "real demand," sometimes it’s just everyone paying for the next round of filters.
Anyway, I first ask myself when looking at the data: can this money leave at any time, or is it just sitting in the reports?