Shopify comes packaged with a robust shopping cart that allows you to take credit cards without the regulatory and security burdens of handling the transactions directly. You don’t have to worry about being “PCI Compliant” as they take care of most of that and ensures that your business qualifies. With Shopify, the customer’s credit card number is not seen by the merchant (you) so customers feel more comfortable entering their credit card on your store.
Yes — you can get a PayPal or Stripe account but be sure to review the cost of using those services including the fees they charge which are not refundable even if you refund your customer.
Shopify also gives you the ability to integrate other services like PayPal, Amazon Pay, Shop Pay, Google Pay and even to accept checks.