I think the helpfulness of the radicals varies from person to person. Personally, I’ve found it really helpful to have ANY name for the various pieces that make up kanji. I had prior kanji knowledge coming in, so when I saw new kanji I would recognize parts - but not always enough to be able to accurately describe or recreate them even directly afterwards. Just having names for the building blocks has made it much easier to distinguish and remember kanji with similar pieces, or to remember kanji long enough to draw them into a dictionary app or something.
Plus, as others have said, many of the meanings do correspond with actual kanji meanings, in which case they’re especially worth learning. (Most or all of these list that close meaning on the examples tab when learning it, too.) And of course some of the most outlandish mnemonics can be, I find, the ones that end up sticking best.
…but all of this is definitely in YMMV territory. Just worth trying and seeing what works for you personally 
P.S. In case you don’t already use it, there is a script for adding user synonyms during lessons you might be interested in, so you don’t have to manually go to the page later: [Userscript] WaniKani Lesson User Synonyms v2