At the moment, you can easily exchange PayPal to Bitcoin, despite the different operating principles of the two systems. Each of these networks exist in parallel modes, touching only if currency exchange is necessary. But the current situation is just a truce in a long battle. Bitcoins outperform many competitors in the Internet space, leading in many respects. Crypto currency, which exists for about 7 years, was able to bypass competitors working for centuries.
Despite the fact that it's easy to exchange PayPal for Bitcoin today, you need to choose a good exchanger that has an excellent reputation. By using the PayPal service, you can purchase a crypto currency, but for this you will have to use the services of intermediary websites. And this will lead to certain losses on commissions.
The whole topic is about the fact that it's not easy to use Paypal to buy bitcoin or any crypto. Anyway, it's not possible to buy the other cryptos directly (maybe ethereum) but bitcoin, and you have to exchange the bitcoins in order to buy the other cryptocurrencies.
If you want to buy bitcoin with Paypal, nobody will be selling you any bitcoin (or maybe only with huge discount in the exchange rate to cover the risk of the paypal dispute/claim). Paypal is known that it's automatically decides in the favour of the buyer if the disputed transaction is about cryptocurrency. When you buy bitcoin with paypal, you can start a dispute and escalate it to a claim, stating that you haven't received anything. Paypal will decide in your favour, they will charge the seller's account and will credit your account. This means you will have the bitcoins and the money in the end. This is why nobody wants to be a seller when the buyer wants to use Paypal.