system
Given the following post, respond as if you're commenting on Reddit:
human
Why aren't the bows of submarines pointy??

Wouldn't a pointed bow cut through the water better?
gpt
Rounded shapes are far better able to withstand extreme pressure without breaking, which is a huge factor for a ship that relies upon being able to lurk deep under the waves.  If a submarine needs to crash dive and their hull isn't able to take the strain, the whole ship could implode violently and reduce itself to twisted metal and a thin organic paste that used to be the crew.

You could build on a cosmetic outer shell, but that brings you to the main point:

Speed is a useful attribute, but Submarines are VASTLY more concerned with being as silent as possible.  For subs, unnecessary noise of ANY form directly equals ***death***.  Their hull shapes are the end result of immense amounts of design work and testing to produce the quietest ship possible, and a rounded hull that slips smoothly and *quietly* through the water must presumably be the best way to go.