Street photographers have a saying: “zoom with your feet.” If you need to get a better look at your subject, move closer. Besides being a quintessential artistic tip, it’s the better option as the digital zoom on smartphones is virtually useless.
With very rare exceptions, all your camera is doing is cropping the image before the shot is taken. Though you might get by in the daytime, in low light, this is triply problematic – digital zooming exacerbates any shakiness in your hands, amplifies noise and lowers resolution.
Of course, you can’t always move closer to your subject, but in that case it’s almost certainly better to just crop later. After all, you can’t uncrop a shot that’s been taken.