You have to put it in context with what passed for a smart phone back then. No web browser (they sort of existed but were extremely cut down and not really usable), small screens with limited software, very limited connectivity that was very expensive.
A valid criticism was the lack of physical keyboard, which phone-jockies found a deal breaker, but in all other ways a phone with decent apps, a large screen, a real web browser designed around and provided with unlimited internet connectivity was always going to be a hit.
It wasn't even that expensive compared to other phones.