All of those require the user to then move the cursor after starting the selection (by character, word or line). The proposal is to use context to grow the selection by repeating the same shortcut, first the word, then the sentence, then the paragraph. Their audience are creative writers, not code writers so they (the audience) are probably not even aware of vim.
My only gripe with their choice of using the Shift key is that then you can't use Shift + the original shortcut to shrink the selection.
My only gripe with their choice of using the Shift key is that then you can't use Shift + the original shortcut to shrink the selection.