It's a tradeoff for mitigating other, perhaps more realistic attack vectors.
the effective entropy of your key could be halved simply by one of the PRNGs being compromised
Halved is a whole lot better than wholly negated, which was the point of the suggestion.
Cryptography is hard.
Yeah.
Architecturally, though, it seems that (dis-)trusting two supposedly PRNG sources is better than all eggs in one basket with one.
It's a tradeoff for mitigating other, perhaps more realistic attack vectors.
the effective entropy of your key could be halved simply by one of the PRNGs being compromised
Halved is a whole lot better than wholly negated, which was the point of the suggestion.
Cryptography is hard.
Yeah.
Architecturally, though, it seems that (dis-)trusting two supposedly PRNG sources is better than all eggs in one basket with one.