The comparison you stated doesn’t make any sense, as “telephoto” is more of a generic term which relates to longer focal lengths. The periscope lens is just a telephoto lens with a different construction:
Smartphone camera lenses are fairly limited in terms of size, that’s especially true for telephoto lenses. A way to work around this issue is the periscope design. Instead of having the lens sitting right in front of the sensor, it actually sits in a 90° rotation with a prism redirecting the light through the lens to the actual sensor. I didn’t quite get whether the periscope lens on the 3a is actually a fixed focal length or us a zoom lens which operates between two focal lengths.
It at least have been said it would be a 3x “zoom”, which would mean ~72mm focal length, which is a good one for portraits and is classic, traditional focal length for portrait shots.
