I don’t know about “inferior”, but I would expect that it is harder.
When I lived in Hong Kong a lot of my ethnic Chinese friends were tri-lingual – they spoke English, Cantonese and Mandarin. Most of them (but not all) could also read both simplified and traditional Chinese. But fewer of them could write it. And fewer still could type it (which seemed to be a much harder skill).
I think that contrasts with English in two respects. Firstly, I think I would say with reasonable confidence that there are far fewer people who speak English but cannot read it. That suggests to me that mastering literacy in Chinese is harder than it is in English. Secondly, I cannot think of anyone I have ever met who could read English but not write it. And I am certain that I have never met anyone who could write English but not type it out on a keyboard. That also suggests to me that written Putonghua is considerably harder to master relative to the language itself.