I mean the Obtainium;

As much as Google/Apple/Aurora/F-Droid Stores censor and blackmail devs, and compromise the privacy, they do provide some security guarantees (automated checks for malware, and other vulnerabilities, and potentially triggering manual reviews).

Going directly to the source gives you faster updates, privacy, and undercuts the censorship. But if the dev decides to be malicious, or is hacked, and pushes some compromised release on github, there's no stoppers.

So it's a tradeoff; and depends on the privacy/security threat profile. I can see there would be a demand and market for non-censoring security-guaranteeing app stores. Obtainium is just a 'release tracker' imo.