I think it may be grounded in ironic hyperbole.

You might deconstruct the statement:

This is of earth-shattering importance and I'm horrified, devastated, since our entire civilisation, indeed humanity itself, is doomed to utter destruction, but… it could be worse.

Perhaps there's a little touch of Yiddish there which might confuse those without a finely-developed sense of guilt.

The other construction is both literal and very old:

Not a whit, we defy augury: there's a special
providence in the fall of a sparrow. If it be now,
'tis not to come; if it be not to come, it will be
now; if it be not now, yet it will come: the
readiness is all: since no man has aught of what he
leaves, what is't to leave betimes?

--- William Shakespeare, Hamlet, act v, scene ii

Far from illiterate, the phrase has an ancient and respected history.

Cheers,

Puddin'

In general, there are no right answers or wrong answers to any question about English usage, because language is an art form, so the only real question is, "Does this string of English words please me or not?"

The answer may vary between different English speakers and listeners, and eventually everything changes, because people are never satisfied with saying the same old thing, and everyone is engaged in "tweaking" the language to achieve some desired efect or another*.

We're so annoyed, in fact, by trite sayings copied from someone else, that if you do too much of it, you may be charged with the crime of plagiarism.

Cheers,

Puddin'

-----------

* Which is why…

Hwæt! We Gardena      in geardagum,
þeodcyninga,      þrym gefrunon,
hu ða æþelingas      ellen fremedon.
Oft Scyld Scefing      sceaþena þreatum,

…doesn't make much sense any more.

And even…

Whilom, as olde stories tellen us,
Ther was a duc that highte Theseus;
Of Atthenes he was lord and governour,
And in his tyme swich a conquerour,
That gretter was ther noon under the sonne.

…looks a little odd.

-----------

`…There's glory for you!'

`I don't know what you mean by "glory",' Alice said.

Humpty Dumpty smiled contemptuously. `Of course you don't -- till I tell you. I meant "there's a nice knock-down argument for you!"'

`But "glory" doesn't mean "a nice knock-down argument",' Alice objected.

`When I use a word,' Humpty Dumpty said, in rather a scornful tone, `it means just what I choose it to mean -- neither more nor less.'

`The question is,' said Alice, `whether you can make words mean so many different things.'

`The question is,' said Humpty Dumpty, `which is to be master -- that's all.'

--- Lewis Carroll, Through the Looking Glass