Why do they still make them?
It’s possible with pear head ratchets, and other ratchets with a reversing lever, to accidentally switch the ratchet rotation if you drop the ratchet, or bump the ratchet against something.
Round Head Ratchets with a reversing ring can can have the same issue if you don’t pay attention.
With push thru ratchets, once the socket is placed on the ratchet, it’s obvious if the ratchet has bern reversed, because the docket would get knocked off in the process.
Also, some push thru ratchet designs also allowed the square head to be pushed completely out of the ratchet, in case you needed a different head size or a specialty design.
Some older specialty ratchets were also made with a thru head design that allowed the ratchet to be used as a pass thru ratchet, and for these there were push thru square drive ratchet adapters so the ratchet could also be used for square drive sockets.