Zelle at least is completely free to use. It's owned and operated by several major U.S. banks and integrated into the banking apps of over 1,600 U.S. banks - something like 80% of the U.S. banking population has easy direct access to Zelle via their own bank's app or website. Transfers are typically instantaneous. I use Zelle regularly to transfer funds to myself from one bank to another and my balances at both banks are adjusted within seconds. Both of my regular banks have Zelle incorporated, so I log directly into the bank's website to access Zelle.
The downside of Zelle is that it is near impossible to have funds reversed if someone else scams you into sending them money, or if you accidentally send money to the wrong person. Because the funds are going directly from one bank account almost instantly into another bank account, with no middleman, there's no going back if you make a mistake. So with Zelle its extremely important to know your recipient and not fall for any kind of phishing or social engineering. My primary bank has a daily Zelle limit of $1,000 and a weekly limit of $2,500 - most likely to limit the damage from elderly citizens falling prey to scammers.
I personally have only had awesome experiences with Zelle, and since there are no fees, it's sort of a no-brainer for transfers between U.S. bank accounts. I'm not sure why anyone who has Zelle access via their bank would still use Paypal or CashApp, except for maybe commercial transactions in which the PayPal buyer protection might be more important to you.
The initial hurdle, like
@earlyretirement mentioned a few posts back, is having the confidence and trust to send someone in BA a Zelle transfer for the first time, especially if you're new here (like me). I'd probably be hesitant the first time unless I was standing right next to the recipient when I push the "send" button. But once the relationship and trust is established, and since Zelle doesn't have any fees, it seems like it's a better way to go than approaching random people on the street with a bag full of pesos (and in my case broken Spanish as well).
I get that Zelle is really only a decent option for U.S. expats though. Folks from other countries may be forced to use other money transfer providers where the percentage of the cut is too large and perhaps buying dollars on the street might make more financial sense.