Goedjn wrote

Nonsense! The byproducts of proper gas combustion is CO2 and water
vapor. CO is not an issue unless something is wrong with the dryer.

Isn't that the point? You can't be certain something won't
go wrong with the dryer and it might end up being too late
by the time you find that out, or your heirs find out...

No. The crux of the matter isn't whether something COULD go wrong,
it's whether something is LIKELY to go wrong. If the odds are
1 in a billion, then it's ignorable. If they're 1 in a million,
then it's probably against code, but it's not what *I*d consider
dangerous. If they're one in a thousand, than it's a dumb-ass idea.

(all relative to the expected gain, which is not all that large,
to begin with)

And its completely trivial to add a CO sensor if you're a neurotic too.

Not a shred of rocket science required at all.