The message .com
from "Wingedcat" contains these words:

Yes the overflow is fed directly into the bowl as part of the flushing
mechanism. Some might say it is inferior to the old-fashioned overflow
out of the side of the wall as it is not as apparent that the cistern
is overflowing.

It's not just that, it's also easier to ignore. I know someone who's
cistern has been overflowing internally for at least a year, but they
just won't fix it. Were it an external overflow it'd be much more
annoying and probably fixed sooner.

--
Skipweasel
Pay no attention to that man behind the curtain.