> Unlike Japanese, Cantonese has a very simple grammar and no registers, so it would be easier to learn to speak.
Registers being different levels of formality (informal, formal, slang, etc)? If so, Cantonese has that in spades.
Your answer also ignores the tonal nature of Cantonese/Mandarin. Most guides can't event agree to how many tones there are. I get by with 7, but it can range from 6 to 10 depending on who you speak to (in contrast to 4 in Mandarin).
Registers being different levels of formality (informal, formal, slang, etc)? If so, Cantonese has that in spades.
Your answer also ignores the tonal nature of Cantonese/Mandarin. Most guides can't event agree to how many tones there are. I get by with 7, but it can range from 6 to 10 depending on who you speak to (in contrast to 4 in Mandarin).