I assume this intention behind this commit is to simplify debugging.
You’re right, it can be easy to set it once you know your path.
But, It took me few minutes to understand Cakewalk got control on my registry VSTFolder. but it’s more fail-safe not to assume this is the folder just as the “default” Windows installation is usually C:\ .
In the link from Steinberg there’s:
This path can also vary due to customized installations and configurations but it is recommended to leave it as it is. Most 3rd party applications predefine the correct path on installation. Cubase and Nuendo can access their own plug-in folder but they can also utilize these shared folders if this has been configured correctly in the menu “Devices”, sub-category “Plug-in information”.
So just as each host could make your plug-in behave differently, many hosts read the value from the registry.
It might be nice that, if you leave it empty, that you’d get the default registry value under Windows.
(just as if you leave your Paths empty within the Projucer they’d figure them out from the default onces in the Projucer preferences).