If the purpose of the wearable device would be to display text, I’d agree with you. But it’s not. And having started with a square smartwatch and having had a variety of round smartwatches, I can confidently tell you that the round shape is just fine for the amount of text needed on your wrist, mostly for notifications. This is called a post-hoc justification, what you’re doing.
For apps or maps, or a particular watch face tweaked for a workout, or just a regular generic watch face, the round shape is the best, you can get beautiful analog and digital faces that don’t look awkward - you just get the largest possible area in the smallest possible object. It’s mathematics.
On top of that, if you have several buttons on the thing, you‘ll quickly discover they’re far more accessible on a round shape. Apple hides this with the sole scrolling button, which is inconvenient in itself. Now they brag they added a second button on the Ultra and the cult followers swoon, best thing since sliced bread. Imagine having 5, like Garmin! As soon as Apple has that, it will be the best thing ever, first to market, they invented it etc.