When WaniKani makes images like this that do a good job showing what the different kana mean, I’m very surprised we don’t see these kinds of images or just any image at all for visual learners on every lesson to really reinforce their meaning to the word. Like all of the examples of Kouichi slowly adding to the pic as we learn would be hilarious and I think more memorable than trying to generate that picture in my own head but that could just be me.
But simply put, of the three learning types I was taught in school, visual, auditory, and kinesthetic (apparently there are more categorized types now), WaniKani so far makes use of only two of the three. Kinesthetic (AKA the hands-on" approach) learners have to type the word out themselves in kana form and auditory learners hear the vocabulary spoken to them on the success of getting the word right. All that’s missing is being shown an image when learning a word and being shown that image again every time you review it to cater to visual learners.
On that note, I think you might really enjoy the Drops app as it teaches Japanese using both words, sounds, and pictures along with gamifying the learning experience. It also restricts you to only using the app for five minutes every 10 hours (unless you get premium) which makes doing lessons and reviews less daunting similar to WaniKani. Side note: For the app, I personally recommend turning off the stroke order mini-game in the settings as it has given me issues that waste those precious seconds you get every 10 hours.