It certainly depends on the individual. Myself, I prefer unlocked and will buy from whatever reputable seller offers the lowest net price, including possible trade-in. A simple trade-in process is nice. For example, Best Buy and Google are both offering the same list price, trade-in value for my existing phone, and gift card value for Pixel 10a, With BB, all I'd have to do is show up and give them my old phone, versus mailing the trade-in. Much simpler. Plus, the BB gift card is better for me as I like the much wider choices at BB.
I've had good experiences buying from Samsung, Google, Best Buy, and Amazon. I don't do carrier offers, but I can see scenarios that work for some.