I finally managed to familiriaze myself with it a week ago. Fucking awesome is what it is. In simplest terms Real-Debrid caches torrents so you can stream them from their servers instead of downloading the torrent. The cache is massive and expands constantly because any time something isn't cached already, it is cached when someone wants to watch it.
I use Stremio with Torrentio addon, it just works. The user experience is much like any legal streaming services.
Real-Debrid conceals your traffic from your ISP by using HTTPS, but the service does keep track of your IPs. It's best to create the account using an email untraceable to you, pay for the service with crypto or paysafecard and always use a VPN when logging in to the site or streaming. There's always a slight possibility that someone manages to hack into the service and use your data against you, so don't provide them any traceable data.
Real-Debrid costs 3...4 dollars per month, it's not expensive. The free or cheaper alternatives are not good.
A good VPN is another 3...4 dollars so combined it's still cheaper than using a regular streaming service. I very much recommend getting into it, just remember to cover your ass.
PS. Real-Debrid caches torrents from like 20 different torrent sites and once they're cached it doesn't matter how many seeders the original torrent has. That means for example that you can stream stuff that wouldn't even be available on the torrent sites you know or use.