WordPress.getCurrentBlog() tries to recover a blog object if there wasn't one previously set, so it's safer to use than WordPress.currentBlog throughout the app.
I would rename getCurrentBlog - it can feel weird the state of currentBlog change after this is called.
The upcoming FluxC integration removes WordPress.currentBlog and WordPress.getCurrentBlog() entirely, and we instead pass the current SiteModel through the app.
RIP currentBlog and getCurrentBlog().
Most helpful comment
RIP
currentBlogandgetCurrentBlog().