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Not all DAWs & software are 64b.

Sometimes it's less confusing or problematic installing both when vendors do an auto install.
You can then delete whichever one you don't want or need.
I use mainly 64b, the few 32b vst/i's I need are in their x86 folders.

cclarry
For many DAW's it's the case of the 32 bit VST's and VSTi's having to utilize Bitbridge or J-Bridge to run
in a 64 bit environment....so, instead, they just use the 32 bit DAW instead and that eliminates any problems
from having to "bridge" your 32 bit VST's and VSTi's....
 
That would be the MAIN reason...

I have 2 32 bit DAW's....Harrison MixBus and Pro Studio, so I have my 32 bit VST's and VSTi's installed in the C:\Program Files(x86)\VSTPlugins folder...and point 
the DAW's there....

Agree with cclarry here.  When 8.5 came out and I first built a 64bit DAW, I was initially concerned about bitbridge mainly for 32bit third party vsts.  So I ran both 32bit and 64bit of Sonar.  There were a few vst programs that I wanted to keep running that ran only in 32bit environment and there were a couple of DXI programs that I ran that do not run at all in 64bit land even with a dxi wrapper.  I also was nervous about stability and also was concerned about projects that I was working on that were 32bit and whether they would make it smoothly to 64bit environment.
 
While I installed both 32bit and 64bit versions of Sonar 8.51, I mainly used 64bit version.  When X1 came out I was still cautious of the new Sonar GUI and layout and I installed both 32bit and 64 bit, but actually I never had to use the 32bit version for any project.  I did play with the 32 bit X1 to see if it was okay, but would only do projects with the 64 bit X1 Sonar.  When X2 came out I just installed the 64bit version and left 32bit behind.  I have no regrets.
 
Until recently UAD and Waves were still 32bit, but with them now 64bit and stable, there is no need (at least for me) to run a 32bit version of Sonar any more.  I do miss not having one or two DXI pieces of software, but I found other native 64bit programs that cover what they did.
 
 So to make a long story short, I don't think you need to run a 32bit version of Sonar X2 unless you have a DXI program that won't run on a 64bit DAW.  Bitbridge and JBridge work great for bridging 32bit vsts into the 64bit Sonar X2a.

I have had trouble (i.e. frequent crashes) when running old projects (previously created in Sonar 7 on an XP platform) in 64-bit Sonar X2, so I now only use the 64-bit version for new projects and always use 32-bit for old ones.
 

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