That's stripe rate. You will pay higher elsewhere.
There are others with similar prices. Adyen: https://www.adyen.com/pricing and Braintree: https://www.braintreepayments.com/se/braintree-pricing for example.
Only if you choose a provider that charges above market rate :)
IIRC, PayPal has offered 2.9% for over a decade
Where do you host your shopping cart? Your download server? “Using Stripe” doesn’t build your system. Stripe isn’t a standalone product. You have to have a developer to run and maintain your system. You have to pay server costs as well. And customer support costs dealing with payments and download and install issues.
And with fraud on Apple, you are never affected directly. For example, a chargeback on Stripe costs you $20, unless you win. If you are doing any sort of volume, that is not only expensive, but time consuming — you have to defend your case. You never touch any of that with Apple. At the very least, you need a developer to both build and “run” your store and all of its associated infrastructure.
Fraud happens with any payment provider including Apple.
You don't have to pay extra for shopping cart infrastructure if you use Stripe or similar