If you’re set to only read vocab and kanji, then yes, if you want to read Japanese texts such as manga or simple books, WK is a fine single resource. If only want to learn Kanji.
However, if your goal is to be fluent, watch Japanese tv, read more complicated pieces of text, pass the JLPT, etc, WK will be more of a side resource that will just give you pieces to use in Japanese. Grammar is very important, otherwise if you’re speaking your just saying words.
WK also doesn’t teach you the different politeness levels and honorific ways of speech, nor does it focus on differences between intransitive and transitive verbs or noun and verb modifiers.
In that sense, WK is a good side resource for a textbook such as Genki. WK teaches you the vocab so when you read a textbook, you only have to focus on how the vocab is used.