Mosul still had tons of standing buildings where Rafah has entire neighborhoods demolished down to the ground. The destruction there is far more systematic because it's intentional and systematized to drive Palestinians out of the area.
Rafah has been demolished to create a buffer zone near the border (after the population had been evacuated). Egypt likewise has demolished Rafah on its side of the border in 2013 to create a security zone.
Just translating what accepting that "demolished to create a buffer zone" is a reasonable justification for levelling Rafah (and a lot of the rest of Gaza) means. Those peoples lives, homes and businesses are expected to just be subject to the whims and desires of the Israeli government all while they allow(ed) the blockage of aid going into the territory and fired on the camps they drove people into.