Eth, tron, or even bsc, whichever one they choose, is in their own selfish interest and not for the growth of the crypto space; what they are after is what can serve their business better and nothing more than that.
 
And beside, it’s no longer news that PayPal was already crypto-friendly since their customers were able to buy crypto using the account and withdraw it to their private wallet. If PayPal was indeed targeting increased usage of crypto, they could have made an open source offer and allowed the community to share their ideas based on what they felt, or better yet, they could have made bitcoin their overarching crypto choice rather than making a move for their own stable coin. What’s the point of all platforms and crypto exchanges having their own stable coin? Is there any special purpose that one will serve that the other cannot?