Some say worth to look around on NZB for rare /old releases
If it's rare it's probably NOT on usenet (someone would have downloaded it and it would not be rare anymore).
Can you find old releases? Sure ... but define old?
Files from 2008/2009 upto 2025 can often be found on usenet .. but you will need more than 1 indexer and most are NOT free!
You also need a paid backbone provider to download from, often requiring 1 or more backup providers in case of missing parts.
Missing parts? Unlike filehosts or your harddisk, usenet stores everything in TINY parts and bits and pieces can go missing (this is become a HUGE problem for releases between 2022-2024)
How come? The daily amount of data uploaded to usenet is something stupid like: 475TB (4 months ago).
No company can keep all that and massive amounts of files are being deleted (seems 2022-2023 was the initial time-frame but it seems to expand in both directions as of late (no actual articles about this as usenet providers LOVE to brag about having 6000+ days of retention, just not everything from the last few years is saved for long).
Is usenet good? It depends what you want. Most scene releases make it to usenet as it all bots uploading (so every now and then you get incomplete releases etc).
Things are deleted very fast on some providers, others are not too bad.
Is it easy? Well it has a fair learning curve to get it set up and find all the sources etc.
DC would be many times easier for older/rare releases if you get into a good hub.
Install app, set it up and off you go.
They are 2 completely different things in the end .. and like dnbx said, DC is free ... usenet is not!