Well, there are plenty of counter-arguments to this article.
But first, these “big” (still smaller than a phone) bike computers are offered alongside some pretty tiny ones.
But if you use your bike computer for navigation, you really don’t want a tiny one.
Big means longer battery life, too. We’re talking days or weeks and not hours, when compared to a phone.
Some “big” bike computers also have features that need a little more space: wind sensor, solar panels, glove-friendly buttons, etc.
I’m totally OK with the sizes. My bike computer is medium size in Garmin’s offerings, and sometimes I feel like it’s too small, but never too big. It’s still WAY SMALLER than my phone, and I don’t have to worry about it being exposed to the elements.
That’s actually one benefit to many bike computers: they can be used offline and/or have no data connection or app.
You could connect it to a manufacturer’s services, and lock down what data is shared.
If I had to pick between a phone and a bike computer for privacy, it would be a bike computer.