Pluto TV is a commercial product funded by ads. Their business model relies on you using their official app or website, where they serve targeted advertisements. If you stream Pluto via a generic M3U player, you remove their ability to show you ads, breaking their terms of service.
Stick to the legal method. Unofficial M3U playlists often come from unverified sources that could inject malicious URLs. You are trusting a stranger’s code.
Developers have scraped the direct streaming URLs from Pluto’s public APIs. These URLs look like: https://service-stitcher.clusters.pluto.tv/v1/stitch/.../master.m3u8