On-line appointment for Chinese visa application

I wonder why do we need to have an appointment to submit and process our visa application. I am a Canadian citizen living in Winnipeg; we do not have a Chinese embassy or consulate here; two years ago, we went to Toronto to get a visa (we were visiting my husband's sibling there); we received it on the same day. I forgot how much we paid; we are going cruising this year and we need a chinese L because we will dock in Xiamen; can you tell me the things that I need to know and prepare before I fly to Toronto; I just want to make that I have everything I need and come prepared. How much is one day processing? Do they accept credit card now? Thanks