May as well be shooting a .22LR at that point. Save yourself the powder...
You’re right.
The only reason I could see to shoot round-nosed pills in .224 is if the thing were long and massive - say, 105gr or more.
The trouble is, no stock chamber has a throat leade to handle pills that long, so you’d end up having half the pill down below the base of the case neck, which means that your pressures start going up, and you lose case capacity.
There just comes a point where a guy has to say “screw it” and go get the right tool for the job. And in dangerous large game, that means something larger than .30 cal and pills > 250gr - better if they’re 300gr or more.