chain plates that "stick out" is a choice made by the designer
. Our outboard plates are flush with the hull because the mold
for the hull created pockets where they fit.
However, I think the other poster meant that one can point higher when the shrouds & stays are inboard because of the jib
position. But that is a choice too because sheets
can be lead on the inboard side of the stays and a sloop
can become a cutter
etc. Modern designs with self tacking jib
often point very high and this type of jib is less than 100% (stays forward of the mast
at all times).
I think it's often the designers wish for aesthetics combined with cost savings that lead to the flat plate cutting through the deck
design. Aesthetics because they think an outboard plate doesn't look good, and cost savings because it is possible to create inboard shroud
attachments that do not penetrate the deck (complex mold
or time consuming manual labour) or even carbon fiber molded ones