It won't be 30% cheaper, they will up the price of packs brought through the app by 30% (maybe over time), so a pack will appear to be cheaper online but will be the same price we're paying now.
First thought captured perfectly in this threads title, why? It's 2022 surely consumers don't want a website!
Second thought someone else said, the fortnite situation surely it breaches the TOC.
Final thought looking at the picture above I won't be getting into the habit if that's the daily incentive - nowhere near the advertising picture shown which was to be expected.