The app looks good.
WaniKani is mainly teaching Kanji readings and meanings. Actually, you might defer studying Kanji until you can speak intermediate Japanese. It doesn’t teach enough vocab, nor in context enough. (So, you won’t understand the meaning well enough.)
Still, learning Kanji separately somehow is required to read more Japanese to expand your vocab. Kanji-in-the-wild learning pattern (outside WaniKani)
This is probably an aspect specific to Japanese and Chinese.