Hey there, @skytowner11
Bo here from Shopify Support
That is a really great question. The main benefit that Shopify Payments would have over PayPal is that when you use Shopify Payments you will not incur transaction fees. Our transaction fees per plan can be viewed on our plan page and are applied to all stores that do not use Shopify Payments. This fee is to cover the maintenance and upkeep of the third party gateways. That said, you can actually use PayPal and Shopify Payments in tandem, giving your customer the option to choose between the two.
As popular as PayPal is, some customers will not have PayPal accounts. Giving them the option of checking out using their card or their PayPal account will help you maximize your conversions, customers love having a choice. Using the gateways in tandem like this will also prevent you from being charged transaction fees.
Let me know if there is anything else I can assist you with, I'm happy to help!
All the Best,