Does a streamer do anything to the data that Tidal provides?


I have been streaming Tidal to my HiFi for the past 4 years with a streamer and a DAC connected to my amplifier (Raumfeld streamer to Musical Fidelity DAC and also Musical Fidelity Amp). I also have an all-in-one system for my summer house (Naim Muso Qb). So, I know the basics and I am only interested in streaming from Tidal.

What I struggle to understand is, what the streamer does apart from transporting the digital signal and therefore why it could make sense to invest in an expensive streamer.

I understand what Digital to Analogue Conversion does and that it makes sense to ensure a good quality, but isn't the streamer just a transporter of data? Does the streamer do anything to the data that Tidal delivers apart from receiving them and sending them to the DAC? 

Thanks in advance, Michael 
mtraesbo
+1 on Aires though i run the Mini via spdif to an Audio Note DAC-3 signature. Love the sound and the Lightning DS app is great.
+1 on Aries.
I purchased Auralic Aries Femto to streamline and simplify my music listening - but some of my gear already had streaming capabilities. I was never satisfied with minim server on my NAS and used JRiver. To my surprise Aries also greatly improved sound quality. The most glaring difference in quality was AES/EBU out from Auralic compared to OPPO 105 SPDIF out (I for years use Jriver and BubbleUPNP to play my collection via OPPO).
In fact, to my amusement OPPO-105 as a DAC (I am not using it now in that capacity, but it is still a pretty good one) sounded better when fed from Aries then if used build-in streamer. Dunno why.
To sum up I do not believe that "all streamers" are the same and "digital is digital". Will the  difference in sound justify the price - it is a different story.
On a similar note, what is the best option for internet radio these days?  I don't want to stream from my computer, and listed to my local radio stations a good deal (most of them have internet radio presence).  I might want to stream some music from Amazon Music from my iPhone.  What would be the best solution here?

@willemj I do not see a digital output listed on the Chromecast Audio specs.
Let me reassure you. I have a few Chromecast Audio streamers, some using the analogue output from the internal DAC, others using the optical digital output. The digital output uses the mini optical connector into the same little slot as the little analogue output does, in the same way some Apple products do. For a test, see here: http://archimago.blogspot.nl/2016/02/measurements-google-chromecast-audio_27.html
The digital output is a relatively unknown feature. I have heard from several people who, like me, were told in a store that the Chromecast Audio only has an analogue output.
On the software side, I am happy with the TuneIn app. It even has a sleeptimer.
My practical experience:

Depends somewhat on the DAC. I used a Wyred4Sound re-clocker, and it worked really nicely between a Squeezebox and an older DAC.

Since I upgraded the DAC, this no longer matters.

Best,

E