"Unnecessary words"

I accidentally came across an article about a dear colleague's work on text messages. The article was titled: SMS PhD: Pointless text messages analysed - immediately creating a misleading picture about the importance and usefulness of her (of any CMC related) research.

But it does not get better, I'm afraid. The article reads "She discovered that people text in the same way as if they were talking, using unnecessary words such as 'oh', 'erm' and often use grammatical abbreviations like 'dunno'."
OK, so hold on a second. Are you saying that backchannel signals (like hmmm, erm, ohh,) or other non-linguistic or paralinguistic cues (like laughter, emoticons, hesitation) are unnecessary?
So why are we using them in the first place? Why are they such an integral part of our face-to-face communication, and more importantly, why do we go through all that trouble typing in these words when we text or message someone?


Let me show you an example I came across today in my analysis. This is a random sample from work-based Instant Messenger exchange between a manager and a team member.

1. Chris (10:32 am) i'm at (phone number) unless you have better cheaper option? 
2. Abel  (10:33 am) Not yet, I'll just call the number above... BTW, sorry about the morning, had some problem with my laptop. 
3. Chris (10:33 am) ? sorry abt what? 
4. Abel (10:34 am) errr...nothing 
5. Chris (10:34 am) ha!ha! 
6. Chris (10:34 am) ok... 
7. Chris (10:35 am) call me whenever, i'm still preping for the call myself 

These guys use quite a few strategies to make sure that both of them get the intended meaning (both WHAT they meant and HOW they meant to) - hesitation (...) is one of them, BTW to signal topic change, the extra question mark in line 3 to indicate a puzzled look, and errr . 
Have a look at the same exchange without this 'unnecessary' word: 

1. Abel  (10:33 am) Not yet, I'll just call the number above... BTW, sorry about the morning, had some problem with my laptop. 
2. Chris (10:33 am) ? sorry abt what? 
3. Abel (10:34 am) nothing
4. Chris (10:34 am) ha!ha! 

Doesn't sound quite the same, does it?  Is err  and the hesitation (...) really unnecessary?