The doc is not very accurate. For controllers organized in subdirectories, only the class name part is upper-cased. The rest are kept as it is.
The main reason for using slashes in view paths is because sometimes we need to specify a view like '/path/to/view'. Using a dot would make it look like '.path.to.view', not as intuitive as the former.
Someone using caps lock by accident (entering HTTP://DOMAIN/ADMIN.USER/) will get a 404 for sites running on Linux. Thats not necessary, since it could be easily corrected according to convention.
The reason I mentioned views using slashes and not path alias, not a big deal, but its used almost everywhere else, so perhaps would be more consistent, and will give the opportunity to store some of them at another place without touching the controller files. For instance: beta layout etc.
EDIT About the views: plenty options with themes for that. Sorry, still very new to Yii
Using slashes is a large security risk - people could then attempt to exploit your website by doing request for …/…/…/…/pwd.etc and the likes with the dot notation regardless of the type of request they can never leave the "application" folder because ever dot will be translated to a "/" so the above request would look for a file in your "application//////////pwd.etc"
If you want to use the slashes you should look more into the CUrlManager