Myth: in-app inventory is always cheaper than web

Myth: in-app inventory is always cheaper than web

'Go in-app, the CPMs are lower.' True on the buy. False on the math that matters.

In-app CPMs do run lighter than premium web, but you pay it back in viewability gaps, accidental clicks (the fat-finger tax on full-screen interstitials), and SKAdNetwork's coarse signal that makes optimization slower. Effective cost per qualified action often lands higher than a clean web placement with deterministic attribution.

✓ Raw in-app CPM genuinely undercuts web display
✓ Rewarded and playable formats convert hard when intent matches
✗ Accidental-click rates on interstitials can hit 50%+ — you bought noise
✗ SKAN's 24-tier value cap throttles your optimization loop vs web's full funnel

Normalize on cost per retained D7 user, not CPM. Web frequently wins once you price in attribution clarity.

Verdict: use in-app for scale and format variety, skip the 'always cheaper' framing — measure on D7 cost.
Best for: buyers picking channels off CPM tables alone.