Coming soon.

http://www.magix.com/au/acid/version/acid-pro-7/

I wonder, what's the benefit of using this DAW?

I guess the advantage is loop based arranging.  Oh wait, all major DAWs can do time and pitch stretching now.  Maybe the workflow would be useful if you wanted to create a lot of acidized groove clips?
 
I have an old copy of ACID Pro 6 (32-bit) from over a decade ago, and it sure seemed special back in the day.  Not sure I will bother with an upgrade now...

Soundwise
I wonder, what's the benefit of using this DAW?

 A lot if you do pattern based music.  It's a great GUI.  At one time some like to use Acid to mix because of the layout.  If it had a full piano roll layout this would have been my choice of DAW.  Acid Pro 7 still runs great despite the last update was when W7 rolled out.  It doesn't have all of the features as Live and it doesn't have its price.  It's still a great piece of software and all of the newer VSTs (32bit) run in it.   

Soundwise
I wonder, what's the benefit of using this DAW?

I was wondering why they haven't integrated features together with Samplitude or v/v as one DAW (or is it?).

This upgrade is about 10 years too late. When acid was released it was revolutionary. So much so that most DAWs started using acidized files. It then became stagnate with versions after 4 becoming same producy with minor changes. The rise of Ableton introduced a product that took loop production light years beyond Acid. Most Daws handle loops better than Acid at this point. I miss the simplicity of Acid, but can't imagine anything significant to make upgrade worthwhile

I assumed that Magix would just incorporate the legacy Acid code and features into their mainstream DAW products.  Or release an updated consumer product like Acid Music, for first timers to experience loop based music creation.
 
But trying to release an Acid update now for pro DAW users, after all these years and other, newer options, is a bit tone deaf of their marketing team.

The problem with trying to salvage acid features for Samplitude is most of Acid's features have been dated for years. Is there really a modern DAW that does not have a timestretching algorithm superior to Acid?

Soundwise
I wonder, what's the benefit of using this DAW?

The workflow is geared towards people who focus on sample manipulation and slicing.  If you remember the days of 8-packs, you would definitely have some appreciation for what it could do.  Even so, I can't help thinking that they might have some catching up to do.

Acid Pro (7 or 8) should be a $49 program, and even that price point may be too high.    I used to love Acid when it first appeared in the market, but it no longer has any appeal when every DAW can handle loops with ease...