Phone photography or also known as Phonetography is becoming popular due to the powerful cameras being equipped on our smartphones nowadays.
One of the reason that I can think of is convenience and portability. You can’t fit a DSLR or even a mirrorless camera on your pocket right? Unless you have a pocket like Doraemon. So instead of carrying around traditional cameras or DSLRs, many chose to use phones to capture and preserve magical moments through photographs.