Why? Should I use that as a default payment method online? Is it that much safer?
paypal is a financial services company that has been dealing with credit card security since the late 90s, and basically their entire goal as a company is to securely settle payments and transfer money.
each of the various web stores you go to probably use a much smaller scale, homegrown platform to process your payments. these smaller e-commerce platforms probably have small teams, like a couple dozen, that manage development and security, whereas paypal easily has hundreds solving the same problem. and paypal also has more money to spend to security audits etc etc and has alot more eyes on them to do security well because they have millions of customers and have contracts with some of the biggest companies in the world.
so the general theory is kind of like an economy of scale sort of thing. paypal has more resources to throw at security, in some cases like 50x or 100x the resources than your typical small scale e-commerce platform.
so yeah, if they offer a paypal option, use it and let them store your credit card number instead of your neighborhood skate distributor's website.