Caporegime
This isn't about eyesight, or preference, or whether scaling is good or bad, or about getting what you paid for.
It ABSOLUTELY is about eyesight. You can’t have a single recommended scaling setting for any display meeting “x” ppi. Different people are comfortable with differing sizes of on-screen items and text. Different applications or use cases might dictate a different setting. A manufacturer “recommending” a specific setting it likely to cause more problems and confusion than just stating the hardware specs and letting the user decide user-based settings.
Again, 150% 1200p at 13” (with a suitable distance from eye to display) would be ridiculously large for my use cases. I’d likely be running 100%.