Ok, a 22 Hornet gets 500 fps less velocity (45 grn bullet, speer 14 data) for half the powder. So it is 17% less efficient for half the investment of powder.
Is it worth it? To some yes, to others not so much.
Lets go one step finer.
A 22 LR (if you can find a round) uses a tenth the powder of a 223 and puts out the same 40 grn bullet at half the velocity.
Is it worth it? To some yes, to others not so much.
To me, the 22/250 is a neat compromise for folks like me that could not find a 220Swift when I sold off my last one. Remember you can always download from 22/250 velocities to 223 velocities or even 22LR velocities if you are careful and creative. You can't take a 223 up to the 22/250 velocities easily and safely.
This is why I don't own a 223 anymore and do own a 22/250.