Victor, I agree with what you said.

I can think of no good reason to not save seeds from catfaced fruits.

In addition to what you wrote catfacing can also be due to too much N and also any disturbance of the blossoms when pollen shedding is occuring, but that shouldn't affect any ovules in the tomato ovary that have already been fertilized ( seeds to be),

Carolyn

Agree with Carolyn. I have saved seeds from catfaced fruit off and on for years with no problems. As you said it is environmental.

Dave

Thank you for your responses. It makes me feel a bit better saving the nicer looking fruit for the table. I hope my catfacing(which is not extraordinary)is not due to much N. I grow in raised beds and add compost and dried manure every year to all beds and throw in a handful of Tomato Tone when planting. A shower of Neptune's Harvest after putting out into the garden is all the feeding they get all season. We have crazy weather here on the shores of Buzzards Bay about the time tomatoes blossom. Thanks again for your answers.
Victor