Popular just because OEMs push it.
How many single camera phones beside iphone SE 2020 and Moto RAZR are available?
"Advantages of multiple cameras are obvious - with more lenses and sensors, smartphones can take better variations of photos without compromising the quality"
Lololol I really wonder about this statement
And yet still digitally cropped in high megapixel cameras are taking better zoom pictures especially in low light versus dedicated zoom sensors
And don't get me started on macro vs wide angle lenses
It doesn't work like that, peoples are tired of many camera.
Only two camera would be enough to do all type of pictures.
That couldn't be more wrong.
It is simply that the most popular brands and most popular models do have triple and quadruple camera, not the other way around.
Or simply put, the good smartphones and those who are marketed the most are the one with quad camera, so obviously they are sold the most.
With two camera we can already have all the main features :
Disclaimer : For those who don't know "zoom" doesn't mean "magnification", it mean changing the focal length/field of view/how big or small the image is.
Continuous zoom mean you have a fluid change between two magnification level, unlike fixed levels.
1) A continuous zoom from a regular Wide/Standard (1x) to an Ultra-Wide (0.5x).
2) A continuous zoom from a regular Wide/Standard (1X) to a Telephoto (5x or more).
Both done with superior/no compromise sensor (Would mean two IMX689, or two Omnivision OV48C) and with a Periscope style layout (Periscope is NOT pop up, periscope is the lens being 90° inside the phone).
And with a good Periscope, the Telephoto could have a big Focus control, allowing to switch from the regular deep depth of field (depth of field is the distance between how close and how far the area in focus is) to a shallow depth of field, which make it ideal for Portrait without requiring any depth sensor for that purpose.
And thanks to deep focus control, having a really close focus distance also make it a Macro (Macro is NOT "close ups", it is way closer than that, usually few millimetres).
Macro should NOT be with the Ultra-Wide, the Focal Length (to simplify you can consider Focal Length as how much the lenses magnify, the shorter the wider the picture, the longer the more magnification you have) of an Ultra-Wide is really short, and because of that, it mean, for having the same Macro as a Standard lens would, you need to be closer.
Add to that the fact that, despite having autofocus, the depth of field is usually really deep, and you get the issue that even if you can have your minimum/closest focus distance really close, you still have a really deep area of focus, meaning for a long distance the image will still be blurry and out of focus.
Real Macro Lens for DSLR have more often than not, a long Focal Length, where it is easy to find close (and above to) 100mm Focal Length, which is on the Telephoto range which start around 70mm.