In europe, the UX flow for someone ordering with a credit card goes: Enter cc info -> wait for 3d-secure notification -> click it -> enter passcode and possibly fingerprint as well -> click approve -> wait for the site to send you back from 3d-secure page -> order confirmed
With paypal, this flow, that happens everytime someone buys from your site, even repeat costumers, is reduced to: Click buy with paypal -> possibly login to paypal again -> click "yes i want to pay this" -> order confirmed.
Some sites even make use of paypal's delivery address API and don't even require you to enter it.
It's really a no-contest that costumers using paypal will drop out of the flow at a significantly lower rate than costumers using a card. In some markets, your busines is dead in the water if you decide to not accept paypal.