As someone not from the US I knew of zelle but never used it, and believed it was a direct competitor to Venmo or PayPal.
The reason I thought it was its own thing was because it has its own app, and a catchy silicon-valley-startup type name, and a brand logo, and all of that.
Contrast that to the UK where the ability to send free person-to-person payments has been integrated directly into the banking system for decades, and does not have it’s own brand, or app or anything.