Crack in second photo is so clean, almost looks like a seem that was mudded without being taped first. It happens. I was looking to step up the completion date of our build and had a contractor come in to tape and finish the foyer. A crack showed up almost immediately. When I dug into it, they ran the tape beside the seem? Missed it.... Too anxious to get to the next job I suspect.
If it is a defective tape job, you could grind it out enough to tape it, re-mud and the crack would be completely gone, provided that's all that caused it originally. A caulked seam, while a faster fix, would always be a little noticable.