It was just what WK deemed to be best to learn as a radical – maybe because they thought it’d be easier to visually see it as a sunflower, maybe because it would work better for later mnemonics in new kanji that utilize the radical, who knows!
But regardless, yes you can trust WK ^^
Doesn’t it show you at the end of radical lessons what kanji the radical will be used in? So if you’re really interested in learning a radical “correctly” if they have a corresponding standalone kanji, then you have an easy click to check out the kanji page and see if the meaning is the same or not – and if it differs, you can use the WK Lesson User Synonyms script to add the actual kanji meaning as a synonym so that you can just learn the radical the way you want 
WK is a tool, sure it may not be perfect for everyone, but it’s definitely efficient and reliable and can be customized to be tailored to what you want from the system should you come across something like this – I wouldn’t ever rely on the radicals for true Japanese meanings otherwise