Thus will is not unique in picking out a future time. Moreover, there are some contexts in which will is not the normal way we refer to a future action.
I've always wondered why there isn't a conjugation of words that signifies future tense, and why we simply use "will" instead of having a specific conjugation for a word. Like in past tense, we have the word "walk" conjugated into "walked". I feel this might be confusing to those learning English as well.