The platform just launched in broader test mode, with a range of 'creators, journalists, experts, and nonprofits' getting access to the tool, but there are apparently a couple of significant issues. The first is that people may well be inadvertently sharing their personal address when they provide a 'tip' and they pay via PayPal. Twitter quickly responded to that concern, saying that it would update its process.
Twitter claims that it's a PayPal issue, as PayPal communicates in its terms, is that when people are receiving payments through the platform, they either select a "goods and services" payment, where their address is shared, or they select "friends and family" payment, in which their details are not submitted. What that means is if you have a business PayPal account, you're likely going to be sharing your address info with whomever you make a Twitter tip to.
The second major problem is that it's just as easy for people to request a payment through the process as it is for them to make one. The Tip Jar process is simply connecting users through to these third-party payment platforms; it doesn't define exactly whether this is to send or receive money systematically. That's already lead to profiles with the new Tip Jar button getting a flood of requests from users trying to trick them into paying out.
The Tip Jar proposal is another element in Twitter's broader effort to provide more financial incentive to keep creators tweeting, which could definitely help in boosting on-platform engagement. I guess this is what test mode is for? Ironing out technical problems? It'll be interesting to see how quickly the platform fixes these issues because the function is a good one in theory.