Yes paypal use crypto but instead of eth many users was expecting the TRON blockchain its faster cheaper and more used.
Eth transactions still too expensive i hope they start use TRON soon
A company like Paypal will not bet on losing their money or jeopardizing their investment in a highly centralized blockchain like TRON with relatively high fees and without any independent development compared to a blockchain like Ethereum.
If you omit USDT then TRON is a dead network and will not have any big trading volumes, but Ethereum has value and tokens add extra value to it. They may change their policy in the future and add more blockchains, and then the additional options may be TRON, but it is not the first choice.
I believe that PayPal must be following some directions from the US and that is why it is like this. Tron is also a good coins and both of the them have transaction fees are similar. I don't think that it is the transaction fee that was considered before PayPal chose to use ETH but there are some other factors that was considered.
If they following some directions from the US then will choose some central blockchains