When Apple Watch got a larger screen last year with the Series 7 update, most commentators just yawned. Apparently screen size isn’t everything. It’s what you do with your watch that counts.

So I was surprised to read recent rumors of an Apple Watch Pro with an even bigger screen. Supposedly, this larger model, with its tougher titanium case, will be ideal for extreme sports. But does a bigger screen really help when you’re bungee jumping? And could titanium ever be rugged enough to withstand whitewater rafting?

Something about all this doesn’t add up. Instead, I suspect Cupertino will position the Apple Watch Pro model as a wearable for endurance sports. A bigger watch means a bigger battery. And in endurance sports, you really need that extra juice.