The beaches around Penzance are not all the same, and that is exactly why they are worth comparing. Some are better for a quick dip, some for a long walk and some for sitting out the weather when the sea air is the main attraction.
Think first about access, tide times and whether you want open water, a sheltered spot or an easy place to base the rest of the day. Jubilee Pool, Marazion and the other Mount's Bay options each suit a different kind of visit.
If you plan around the conditions rather than forcing one perfect beach day, the coast becomes much easier to enjoy. In Penzance, that usually means choosing the right stretch for the weather rather than chasing a single favourite.