I have used a ball lock corny as my primary, but it had a lid that had a hole to fit a rubber stopper and an airlock. If you don’t have one you can basically use the quick disconnect and a length of hose to make the blowoff tube. I believe if you ferment anything more than 4 gallons in a corny a blowoff tube is a must!!! When I do use my corny for primary i take out both diptubes, some people do some people don’t. I figure since having a the diptubes inside will mean you have more to clean and i dont have a long brush to clean the length of the corny. Also since the whole corny is made of SS it is 100% light impermeable, easy to clean, perfect handles, and perfect for size to fit in the fridge for lagering or just cold crashing. I have read of some homebrewers cutting extra inches off their liquid diptube so they can transfer up majority of the beer to another corny and leave as much yeast behind. If you have extra diptubes or plenty of cornys this could be an option for you, keeps everything pretty clean and oxidation to minimal if you do everything right. You should definitely try fermenting your beer in a corny once, then if you ever run out of carboys and have unused cornys you will know what to do.
Edited part → I never answered your question, I have never noticed any difference between using a pin lock or a ball lock keg when in primary. Unless you care about surface area of yeast to beer use a pin lock, but I highly doubt that extra inches of surface area makes a difference.