I think that a burial tends to mean there's something to conceal. It's suspicious circs at bare minimum. Happy to be proven wrong, but as far as I know, people die often from ODs or other health reasons if they're homeless, and people don't tend to bury them. They tend to be found in the open, in an alley, in a derelict building, in a poptent, in a dumpster. That kind of thing. Burial, even in a shallow grave, is a very labour intensive endeavour. You need a robust digging tool, you need uninterrupted time, and you need to have a strong enough motivation to hide the decedent that makes it worth the effort. So, murderers would bury the person, or someone committing, say, welfare fraud and wanting to maintain the illusion the person is alive. A drug user, rough sleeper, or someone involved in the sexworker/client dynamic wouldn't. They'd leave the person where they died, or put them somewhere away from them in a semi public or public place. Of course, I am not an expert, and these are massive generalisations to which there are always exceptions, so take what I have said with a grain of salt and a dose of skepticism, but I don't see this being a natural or accidental death.
Very much MOO