Railgun: Privacy when using DeFi possible ? (zk-SNARKs on ETH!?)

Just came across this project called “Railgun”. It seems interesting but what really caught my attention is the fact they claim to be using zk-SNARKS on layer 1 ETH… is this possible? would this implementation provide any sort of real effective privacy? Found these videos on YouTube as well:

More info: Moonshot Hunter AMA. June 30th, 2021 — Transcribed by… | by RAILGUN Project | Sep, 2021 | Medium
Whitepaper: https://bafybeiakdhweojvf7zvtp2tr32alzam4yyifbolf7fgrmsshalea7fv55m.ipfs.cf-ipfs.com/docs/Railgun%20Project%20Whitepaper%20-%20July%202021.pdf