Why do people prefer using "will be doing" form(future continuous) when they can use just "will do"(simple future)?

Question

I get confused several times, especially in speaking English, when I hear more and more native English speaker prefer to use "be doing" form. When I attend a class the instructor may say "We will be talking about XXX in this class" instead of just simply saying "We will talk about XXX in this class".

And I see this today:

I’ll be showing you how to make a simple Chrome extension dashboard from scratch.

from this blog. I thought that would just be simply:

I’ll show you how to make a simple Chrome extension dashboard from scratch.

So why do they bother to use the future continuous tense when they can just use simple future tense?

Answer 1

The simple future tense is used when an action is expected to occur in the future. The nature of it, however, is unknown.

The future continuous tense is used to indicate that something will occur in the future and continue for an expected period of time.

I’ll be showing you how to make a simple Chrome extension dashboard from scratch.

The process is not going to happen all at once. It will have a duration.

Answer 2

When the action is expected to have a duration, we use future continuous:

• In this episode, I'll be telling you how to do it.

If the action is effectively instantaneous, we use simple future:

• In this episode, I'll tell you my email address

As this is a matter of emphasis, you will find many native speakers use one tense when you might have expected the other. Additionally, subgroups often display preferential and idomatic usage. For example, in parts of England "I can't be doing with it" means "It is too irritating for me to deal with."