If you don't use that, then you're pretty much screwed with Paypal F&F, Zelle, Cashapp, Venmo etc. At least as far as I'm aware.
When I try to purchase something with my credit card directly on Best Buy's website, my order always gets cancelled (presumably something in their fraud algorithm), but when I pay using PayPal, the order goes through just fine.
But PayPal probably existed and was easier for merchants in more countries than other payment services at certain points.
This was mostly due to century old banking regulations and the difficulty for any new type of money processors to get themselves connected to the necessary backend systems to actually do anything.
It had absolutely nothing to do with the qualities of PayPal. In many ways they were simply the only game in town.
Not on my planet and I've run $100m+ through them over the years.