And since people communicate successfully all the time through speech ...

Yes, but. Much speech is filled with hedge words, convoluted phrases, and I'm-still-not-sure-what-point-I-am-making discourse. That stuff needs to go.

There's a fair amount of writing that comes across as if it were literally transcribed from an off-the-cuff spoken exposition, and it is distracting.

In casual speaking it's OK to say, "At this point in time", or, "Let me explain", or, "due to the fact", but if you're taking the time to write you can take the time cut the filler as well.

I much prefer a conversational tone in writing but it works best with some careful editing.