Apparently a lot of photographers are deleting photos that have been sent to curation but not been published on the front page. The portfolio tab of your 1x profile is intended to be just that - a portfolio of what you consider to be your best photos. You can create a big porfolio without even sending all photos to curation and just use it as a very elegant way to display your photos, in high resolution if you want.
The published tab on your profile includes photos that the 1x curators decided fit into our gallery. For your own portfolio it shouldn't matter if the photos are publisehd by the 1x curators or not. Not being published doesn't mean it's a bad photo, many times it just means that we already have similar photos published and we want to have a big diversity in the gallery. This also means that a photo that was not published could be considered later on if you leave it on your profile, which is another good reason not to delete your photos.
So in the profile, upload all photos you conisder to be your best, and if some are published/featured consider it a bonus with some extra exposure. If you don't delete them there is always a chance that they will be published later on.