This is a follow up to this question: Why is Seraph gold?
The accepted answer to the related question above concludes that Seraph appears as gold code when Neo first meets him because he is somehow a "hardware" machine plugged into the matrix, rather than just being a "software" program like those with green code.
I want to better understand what that accepted answer proposes, hence my question is: besides the gold code, what evidence is there for/against believing that Seraph is a hardware machine plugged into the Matrix vs. that he is a software program like, say, the agents?
I am interested in understanding why it makes sense to consider Seraph to be hardware as opposed to software with stronger reasoning than just "colour", which could have been a stylistic choice for any other reason (e.g. as per DavidS's comment on the linked question, or simply that gold represents how angelic Seraph is, or maybe even just to make the audience go "Huh? Who's this?", who knows?).
In other words, if the movie never showed Seraph's gold code, would we have any other reason to suspect that he has hardware rather than being entirely software like the other non-human characters we meet inside the Matrix?
This question is not just "No seriously, why is Seraph gold? I don't like that other answer", since it's not that I don't like Null's answer; it's a reasonable conclusion to draw. I also believe that other explanations as to why Seraph's code is gold should belong on that other Q&A, not in a new Q&A. I'm just looking for non-colour-related evidence to explain this aspect of Seraph's nature, even if that answer is "there isn't any further evidence; gold code is all we've got to speculate on".