Will is certainly one way of talking about the future, but is it a future tense?

Will is a modal verb rather than a change in the form of the verb itself, as in write - wrote , which is how I would define a tense.

Why choose will as the future tense rather than for example is going to ?
I'm going to visit my aunt at the weekend refers to the future.
"Who can that be at this time of night?" "Oh, that will be Candi. He said he was coming round." , and She will drive too fast, even though I've told her often enough to slow down do not refer to the future.

Bingley

Bingley