Yes, because the checkout page gets revenue ⇒ the bottom line.
The points you say are the things Valve is doing extra to provide value to the customer.
The point I am saying, is the first thing that anyone working for money needs to care about.
steampowered checkout page:
- loads in a reasonable time
- has the same colour theme as the rest of the website
Epic checkout page:
- even the in-app checkout page is slower than the Steam web checkout page
- is slow not only before loading but also after clicking the ‘place order’ button
- White colour on dark theme website/app