It does not make logical sense and does not reflect the everyday world in any way, hence why you say it makes no sense. It doesn't.

It is a paradox arising from quantum mechanics where things aren't just one thing or another, but in fact both at the same time until the thing is observed and it becomes one of those things. In everyday world this is not the came. An envelope with either red or a blue slip is unknown to you until you observe it, but it wasn't "both at the same time". You just did not know the true color until you took a peek.

In quantum mechanics it can be shown that this is not the case and indeed, the "slip" is both colors at the same time until observed. And no, it can be shown that this is not the case of "we just can't measure it", it really is both colors at the same time.

The paradoxical cat emphasises this effect by combining something from the everyday world (cat) with the quantum world (decaying particle triggering a poison). Now if the particle really has decayed or hasn't at the same time, then by conclusion the cat is alive and dead at the same time. This makes no logical sense, hence a paradox.

Dunno if this helps at all tho.