Is there any reason why 蔵 and 倉 have different definitions? They both have the same reading and in the explanation for the reading for 蔵 it says:
The reading is the same as the other storehouse reading (倉) you learned earlier. They’re both basically the same thing, and lucky for you they share the same reading too (くら).
So even there it says they are the same thing and they have the same reading. However, even though the explanation says the other means storehouse as well, storehouse is not an alternate definition listed for 倉. The definition for 倉 just says warehouse and the definition for 蔵 just says storehouse. Jisho lists both warehouse and storehouse for both kanji and in fact defaults to a single definition for both with one just listed as another form of the other.
So I’m wondering why Wanikani makes the distinction. Is there a certain nuance to the different kanji perhaps in common use that isn’t apparent in the definition?
Well, as noted (I did make a small edit) the nuance is mostly in how they are used in compounds. On their own, 蔵 gets the most usage when read alone as くら.
Is there any word with 倉 that refers to an object and not to a place/building? I might be wrong, but I can’t recall 倉 being used on words like 冷蔵庫 or 金庫, so it’s usage might be a bit more limited than the other two.
But isn’t that the stuff you have in the 倉庫? I mean, of course the stuff itself is an object, but 倉 still represents a place and not something like an object to put other objects inside, such as 冷蔵庫 or 金庫.