@John-S-Parry said:
At the physical device level. The Garmin doesn't overheat. It can tolerate Death Valley USA level heat and other abuses that a phone can't. Additionally, the Garmin screen is completely readable in glare, while the phone isn't.
This is largely depends on the choice of phone. Mine is military specced with a 3000 Nits brightness. More than enough to be used with a matte screenprotector to reduce glare.
And on the Android side, the rugged versions of phones I've researched don't provide the full functionality of regular phones for everyday use.
Motorola has a large lineup of these military specced high brightness phones. The Edge 60 Neo for example can be bought for around 225 euro, and is perfectly fit to be used as a daily phone. If you are a high-end phone user perhaps it is not your thing, but choosing a Zumo also means an extra device. I bought my motorola dedicated for navigation alongside my daily pixel.
But yes, a Zumo can be, under specific conditions, be preferable. It would be very bad if it could not... I did not mean to start a flame war, thanks for your motivation in favor of an XT3.