A big YES
The MORE books you have may equals to the higher chance that you master the language
The MORE time you spent on studying the language “truely” equals to a good performance
A good book = shortcut to the core part of the language
BOOKS are not expensive, WHY not?
They are good reference, always available 24hours 7 days
They are structural – in great details
you can learn on your own pace 😀
(yes, you will probably get some useless books / apps, take the risk, you can go to youtube to take a look of the comments on related books)
I strongly recommendation “Lonely planet phrase book” (best suit for who wants survival Cantonese, best suit for upper beginner & intermediate, as for beginner, it is still something relevant to read, so don’t miss it)
(sold 10 million of copies, I guess people really like it)
Do not buy Sidney Lau’s book, it is not for self learning, but you can challenge yourself.
Betty Hung’s book are good.