I'm just curious more than anything.

Some VST3 installs as a folder which then includes a structure before getting to the .vst file itself, such as:

Cradle The God Particle.vst3 (folder) > Contents > x86_64-win > Cradle The God Particle.vst3 (file)​

Whereas others just install a straight up file, such as:

ShaperBox 3.vst3 (file)​

I know one DAW (can't remember which) you had to navigate into the folder to dig for the VST3 file itself, whereas some present it without having to dig through.

Why the difference? And does it matter?

 

Yeah it seems weird, but more annoying is when you attempt to install over top and it can't create the folder because there is a VST3 with the same name and extension (as the folder is also named with".vst3")
I thought i would not touch my vst3 folder, but I ended up creating vendor folders for the ones that just drop their files in the main folder.
I have quick shortcuts to the VST folders so it's very quick to look and see / move stuff.

Some VST3 are just "wrappers" for the VST2s, and I recall R2R suggesting just using the VST2 for that type of one product.

 

VST3's are application bundles, which are basically folders that contain the main binary (DLL file on windows) and other resources like graphics all in one. They just show up as single files if a file attribute is set correctly (sometimes). Older versions can be just DLL files like VST2 plugins.

Code:

/c/Program Files/Common Files/VST3
$ file Solaris\ \(64\).vst3

Solaris (64).vst3: PE32+ executable (DLL) (GUI) x86-64, for MS Windows, 3 sections

/c/Program Files/Common Files/VST3$ 
file Phosphor3.vst3

Phosphor3.vst3: directory

/c/Program Files/Common Files/VST3
$ file Phosphor3.vst3/Contents/x86_64-win/Phosphor3.vst3

Phosphor3.vst3/Contents/x86_64-win/Phosphor3.vst3: PE32+ executable (DLL) (GUI) x86-64, for MS Windows, 7 sections

Macs have had these for years, also called "fat binaries" because they can also contain the code for several processor architectures.

 

I think you're right on this. Quite a few plugins out there are just VST3 wrappers which is a lazy way getting into "new standard".