the point of using number in the domain is, a lot of Chinese people don't know letters, they don't know English words and they can't get "PinYin"(using letters to represent Chinese words) right. How do you make these people type urls in the browser? well, luckily, they all know numbers!
Are there really computer-literate Mandarin speakers in China who don't know pinyin? How do they input text? The only serious non-pinyin IMEs I'm aware of are the bopomofo ones for traditional characters in Taiwan.
Mandarin speakers in some parts of China speak their Mandarin differently, so can't remember the exact pinyin. E.g. around Wuhan people can't remember whether a word ends with -ang or -an, similarly with -eng and -en. As a foreigner, I can't remember nu and nv, similarly lu and lv. Beijingers have trouble with -r endings.
many older people like my dad, don't know pinyin well. he doesn't input texts, but he browses web sites. He uses a default home pages full of links to start exploring the web.
