Serious question: how does Bandcamp manage purchases? Are you buying a "license for listening to music" or can you actually download a DRM-free copy etc.?
You can get a ZIP of OGGs if you want. Those will last as least as long as a 2005 DVD rip from Pirate Bay. Feels good.
(You can also stream through their site and app, and I think they have all sorts of social features... but you can ignore the hell out of it and just get tunes for money. Really one of my top 5 sites, Bandcamp, though I wish they were still independent.)
Zip of FLACs even. As space is cheap and abundant (or at least for me, buying only about 6-12 albums / month) that allows me to not worry about transcoding into whatever at some point in the future.
Indeed, what others have said. Bandcamp files are DRM-free, and they say as much on their site. The only time I use their app to listen is when I'm driving, since the app plays nice with Android Auto, but you can use any capable player you wish. I have probably purchased around 200 albums from there over the years with an average of about $12USD per and discovered TONS of new-to-me artists from there. It is my sole source of music these days and all my purchases are backed up on my home media server in the event Bandcamp shutters its doors or does something ethically stupid.
In addition to streaming, you can (and should) download the mp3 or flac files. Once you have them, they are yours.
Be warned though, the artist/label can decide for whatever reason to take the music they have listed on the website down, which includes what you’ve purchased, so while it’s rare, it’s possible for things to just disappear, so make sure you download before then.
I just create a tmux session on my proxmox homeserver and copy+paste a command whenever I make purchases. I can paste the command I use tomorrow if anyone likes.
I recently learned that foobar2000 can load the zip files of songs directly without having to unpack them, which is nice.
You get DRM-free copy, and unlimited amount of downloads for the music. In multiple formats, including flac and nowadays quite often 24bit flacs are also available.
I once bought https://djemynai.bandcamp.com/album/zao. Once is the keyword here, because it allowed me to download the audio files. You are essentially paying for the ability to be able to download, and then you are free to do whatever, just like old times. :D